I'm a straight male. I realize some of these have been mentioned to some degree....
Handjobs- They are shitty. Obviously, I can do that myself. The problem is more that it's really, really hard for me to get off that way and a few of my partners have decided that the answer to that is to grip way too hard and go way too fast. I once had someone tear my skin from doing that.
Cowgirl- When the girl's being selfish. I've got no issue with letting her control things some of the time, but there's gotta be SOME MOVEMENT! Need some friction if it's ever gonna end for me.
I was with someone that was completely fixated on nearly 100% pressure. She would crush down on me until she came.
I'd end up having to flip her over after she was done and finish in missionary. All while knowing full well she was already done. Which would then get in my head and make it take even longer.
We eventually worked it out so that I'd let her know when she needed to slide up/down and we'd split the time. Worked OK.
Girls that are way too self conscious- I understand most people have parts of their body that they're not thrilled with. But.... I wouldn't be with them if I was gonna get somehow turned off by a few stretch marks or tiny breasts, etc, etc.
I love the sight of it all. Lights off or articles of clothing left on, on a routine basis sucks.
Going down on someone and getting my head shoved down when I hit THAT spot. I realize it feels good and all. Want more pressure? All I need is, "Push harder with your tongue, please."
Girls that think a ton of deep throat is gonna get me to finish. Some deep throat is really hot. Feels good, looks good. It may get me to finish quicker but it's never the actual catalyst to getting off.
Doggystyle- It feels dominant and that's good. It's just that as far as the actual mechanics, it doesn't work near as well as other positions.
Someone that assures me it's OK to nut in her mouth. Then when I do it, they spring up and run to the bathroom like there's a grenade in their mouth.
Before anyone says anything.... My diet's normal, I don't eat a ton of red meat or anything like that. The girl I'm with now says it tastes fine/normal.
Being too unselfish- I like some fairly hardcore, rough acts, but I hate it if she's not into it, too. In other words, if someone's just going through the motions for me, cause they're trying to make me happy. I appreciate it. I'd just rather do stuff that we're both gonna truly enjoy.
Also, a part of this is someone who's not completely forthcoming about what they like or love. I've been with a few girls that despite my reassurances that regardless of what it is, I'd at least like to hear what they're kink is, they will not spill the beans.
Usually, except for a couple frightening exceptions, the act or request is far less "weird" or embarrassing then they thought it would be. It's usually fine and then they get it. But, there was those weeks or months where I could have been making them happier that weren't wasted, but also weren't at their full potential.
There's more, but that's enough. I guess a few of those sound more like pet peeves, but sometimes it can be a really minor sounding issue that's the difference between good and bad.