I wouldn't limit it to rock but anything that sticks to one time signature is pretty simple. Any 4/4 or 3/4 or 6/8 is easy to count. Then you have rock groups like Tool where the drummer is playing a totally different time signature than the guitar and only sync back up on least common denominator multiples. Jazz gets crazy too like you said.

What's weird is there are bands that deliberately play odd meters in their time signatures to match some sort of math concept that is just no where near the same likeability as what Tool does with their Fibonacci sequence and other things. I don't know if they are just lesser musicians, but it definitely feels forced. This is what I notice a lot about some jazz where they are doing it for the sake of doing it not because it sounds good.

It's definitely a case of learning the rules so you know how best to break them. If you just start breaking them without knowing why they are there in the first place just sounds bad to me.