The first thing you need to keep in mind about any real job is that work is normally exploitative, and big tech jobs are no exception. They give great starting salaries compared to other junior developer positions, sure, but there's a catch. They lose money on you during your first year working there with no experience with the expectation that they will make that money back from your labor later on when you know what you're doing there. Big tech companies like Amazon and Facebook often use their own, internal, company-specific tools that aren't used at other companies. For example, Facebook created and uses the Hack programming language that nobody else uses (it started as an offshoot of PHP with types added and became its own separate programming language sort of like how C++ started as C with classes and then became its own separate thing). Amazon's core services run on Amazon's unique internal deployment engine called Apollo, which you can read about here and are built by Amazon's unique internal build system, Brazil. Most companies put their applications that run on servers in containers like Docker, deploy/scale their containers with say Kubernetes, and can use the AWS Elastic Container Service (ECS) that handles the deployment and scaling of your containerized apps automatically. For building, they may use a common, open source build system like Maven for Java, sbt (Scala Build Tool) for Scala, or whatever build system your programming language normally uses. The problem with only using and mastering tools that are only used by one specific employer like say Facebook or Amazon is that they don't teach you what is commonly used outside of that company, so what you were taught isn't as readily transferable to another employer if you get fired or choose to leave. Essentially, there is some "employer lock in". You may look around at the facilities at say Amazon or Google and go "golly, gee, there's the Super Smash Bros videogame in the lunch room as well as games and free food, wow", but that stuff isn't just there to make you happy, it's part of the "employer lock in" to keep you from leaving. Once you're locked in and are acquainted with their tools and processes and stuff, they're making profit off of you. If you instead worked at a "regular" company using "regular" commonly used software tools like say (on the backend) the ASP.NET Core framework if you're coding in C# or Spring Boot for Java Spring, you will have skills that you are already deeply familiar with that you can immediately transfer over to another company. At Amazon the backend was in Java which is a common programming language, sure, but they used their own unique custom internal framework called CORAL framework which I think had some Java Spring in it but was a totally custom thing, not the usual stuff that's used at other companies with Java backends. Also, unlike with common open source frameworks and tools, there are no books on say CORAL Framework or the Hack programming language that you can buy on Amazon and read before bed the way there is for say Java Spring or Docker or whatever (which is an issue for me personally because I learn by reading technical books).

When the money supply shrinks or a recession happens causing layoffs, or your performance isn't great, you can get fired, and when that happens you want to be able to find another job quickly and be useful at that job. Sure, having "Amazon" at the top of your resume gets the attention of recruiters from India on LinkedIn, but once you get past that stage you have to actually demonstrate your usefulness to prospective employers on their particular system. I've had prospective employers tell me, as part of their interview/hiring process, "build a JSON API that can be used to play a simple card game" or something like that, where the deck of cards is represented as an array of integers. I can't build that HTTP REST API with Amazon's CORAL Framework because that framework doesn't exist outside of Amazon. Instead I have to learn some common, open source framework that is generally used, like maybe Java Spring Boot or Express on Node.js for backend JavaScript. And like if I work for Facebook and I've been exclusively programming in the Hack programming language for 4 years and then all of a sudden I get fired because there's a recession, I can't do the coding interview at other companies in the Hack language, other company's coding test probably doesn't even support it. I have to learn and use something more common that other people and companies know, use, and support.

So definitely keep that in mind and have a second/backup tech stack and skill set handy with demo projects that use it in case you ever get fired and need to find another employer outside of the FAANG/MAMAA companies. Ultimately a job is just an exchange of your time for money and an employer is just a source of money. Some people embrace the idea of living to work, but really you should be working to live. Before you accept an offer, establish how many hours a week you will be working so you can have a life outside of work. Don't make your employer think that putting in Herculean (like Hercules) effort is the norm, causing you to get burnt out in the long run. First and foremost, watch out for yourself. Amazon is just another company, and they will put their customers, their shareholders, and their leadership/executives before you, their worker.

Edit 1: One person commented "but the big concepts carry over between companies". And they can, like common object oriented programming language features can transfer over from say Facebook's Hack language to say Python or like the concept of container deployments can transfer over from Amazon's Apollo to Kubernetes. But there's definitely a learning curve and it's not instant, and also in my case I have issues with my brain which made learning new things increasingly difficult over time. If you know what skills/knowledge you need to learn or transfer over ahead of time and put in the work to do it before you get fired it's usually not that bad, but in general I don't like any sort of specific lock-in and in some places lock-in is an intentional feature and not a bug.

Edit 2: Also, even though the starting/junior salary at FAANG is higher than at "normal" companies, if you never get into leadership, management, or anything upper management or executive, their mid to late career pay isn't that amazing. Yes, you get a pay bump from L4 (junior) to L5 or L6, but then your pay from then on is flat forever. If you used "standard" technology and built systems for "regular" companies for that duration of time you could be designing/architecting whole systems from scratch at other companies, setting the rates, and getting paid better than what Amazon would be paying you. One guy described it like this "if the system is a car, at Amazon I was fixing the tailpipe while at this other company I designed, built, and installed the engine". The same person, after 10 years at Amazon, could still be designing and building tailpipes while at another company they could be designing and building the engine or even the whole architecture of a car from the start. Your job title at a non-FAANG company could be "enterprise architect" instead of "senior developer" at FAANG. See this comment.

Edit 3: Oh, and at Amazon you sometimes get woken up by the pager at 3AM because you're "on call" and something bad happened with the system. See this comment.

Edit 4: Also, FAANG jobs are more likely to be in very high cost of living areas. After I left (was forcibly asked to leave) Amazon with less than 2 years of experience in total, I got a job coding for a bank at $86 an hour on W2 in North Carolina where my rent 3-4 blocks from work in the center of town was about $1350 a month. Yes, your pay at say Google is a little higher then where I worked after I left Amazon, but your cost of living in Silicon Valley (and even other locations like New York, Seattle, and Washington DC) is much higher.