This was about a year ago and we were in the start of a new campaign. We had 6 players, 3 new timers, 3 vets, and myself as a semi-vet DM.
They were around level 3 and were taking their subclasses, and a player told me that she was hesitant on taking a subclass because I (as a DM) would restrict what she could do. I asked what she meant, and she said the DMs she played with would do look at player's sheets and make encounters that would try and counter everything the players could do.
She gave me an example of when she played a wizard at her old table, she just learned fireball, and her DM kept sending fire immune enemies at them, so she couldn't actually use that spell. She went about 2 months before ever using fireball. And when players had utility abilities, her past DMs would find ways to counter them so the players wouldn't use them as much.
And that bugged me. Because while DMs should offer challenges, we aren't the players enemies. We give them what the world provides to them. If a player wants to use their cool new abilities, it doesn't make it fun if I counter it right away, or do not give them the chance to use it. Now, there is something to be said that challenges should sometimes make players think outside the box, but for the most part, the shiny new toys they have? Let them use it. Let them take the fireball out of the box. Let them take the broom of flying out for a test drive.