My problems with D&D are twofold:
(1) I am poor at CharOp. Better than I was, I at least now know it is a thing, but I was forever picking interesting sounding options that didn't work in practice - 'trap' options, if you will.

(2) I am truly terrible at giving feedback to the DM when I'm not having fun. Better than I was, but still a bit of a wall-flower, and more to the point, I have far too much empathy for the difficulties of the DM. I don't want to make a fuss. I don't want to be that guy who always whines at the DM.
So, back in the day, I'd pick a sub-par class, or sub-par options, be useless and ineffectual, get bored (at best) and frustrated (eventually) and give up. The DM wouldn't help me by making house rules because:
(1) I would fail to tell them I wasn't having fun.
(2) I don't know if you have noticed, but most DMs - myself included!

- fall in love with their own 'funky' house rules, and fail to notice that: [a] it often wasn't needed,
if it was needed, then it often failed to work, and [c] they almost always had horrible side effects. It turns out that most DMs are not up to professional game design.
And then I found 4E.
This has helped me a lot, for three reasons:
(1) It is so well balanced, that it is very hard to take trap options that will really screw me over.
(2) Its balance means fewer DM house rules, which in my experience have always caused more problems than they have solved.
(3) It explained itself
- what the rules were trying to do, and why it is a good idea to do those things.