I legitimately wish I could experience watching it for the first time again. From the jump the atmosphere is tense, somber, and isolated. The discomfort is tangible from the very beginning. Then the strangers show up. They are and remain strangers to the viewer as well throughout the movie; their identities are never revealed, which I believe adds to the creepiness factor. Then comes the mindfuckery, which is arguably the best part of the movie. The way they toy with the protagonists makes the movie IMO, especially with the slow burn escalation.

The ending is probably one of the best endings to a horror movie I've ever seen; it is incredibly disturbing in the truest sense of the the word. Everything that happens in this movie is well within the realm of reality and that's what makes it so scary. It is unrelentingly nihilistic to the core and I think that's why I love it so much. This is the home invasion movie IMO. Often imitated, never duplicated. Hush and You're Next were alright but they don't hold a candle to The Strangers. This movie is the only horror movie that genuinely scared the shit out of me when I saw it for the first time. Also the sequel is surprisingly better than expected; it's more of an 80's slasher style flick compared to the original's psychological horror. However, the strangers are nigh indestructible for some reason, and the protagonists are inexplicably dumb compared to the first one, which felt more realistic insofar as how an average person would react to such a situation/how the situation would actually play out. The second one can't compete with the first as far as I'm concerned, but I can appreciate it for what it is.

TL;DR: The Strangers is a fantastic horror movie.