When dads take craps and stink up the entire house, so much so that when you come in from outside, even though the bathroom is on an entirely different floor, you know your dad has dropped a load. Why does dad-crap smell so caustic? As far as I can tell, he eats the same food we all do.
Also, my brother who doesn't go to school and has a part-time job staying up until 3:00 or 4:00 in the morning watching TV in his room, and keeping me up all night. Sometimes the guy falls asleep with his door locked, and I can't knock loud or I'll wake my parents up, so there's no way to get him to turn it down!
We have a garbage can under the sink in our kitchen for collecting pop cans and bottles for the recycling bin, to save walking out to the garage every time you finish a soda. Well, as far as I know, my brother has never changed the bag once. Instead, he'll manage to find some way to place yet ANOTHER can on top of the already overflowing mound. I don't know how he does it.
Also, I tend to like to sleep in sub-zero temperatures, just like my dad. If I didn't have an air-conditioner, I think I would kill myself. So when my - gasp - brother decides he wants to be a stubborn little pissant, he goes down and adjusts the settings so the air conditioner turns off. He usually does this after I've gone to bed (remember, he does nothing all day and has no reason to get up in the morning, so he goes to bed 5 hours after me) and I wake up at about 4:00 in the morning sweating like a hog.
I hate watching anyone do any kind of "foot grooming" in front of me. By this I mean cutting toenails, exfoliating, putting foot cream on or anything else involving the foot. Keep it out of my sight.
I drive a transport vehicle as a part-time job, and it involves getting up before the crack of dawn every weekday morning. I also keep my vehicle parked in the driveway, and my brother is fully aware that I leave incredibly early. Yet at least 3 out of every 5 days of any given week, his stupid car is always blocking me in, so I have to go back into the house, find his keys (the ones with three hundred and fifty-six keychains hanging from it) and move it. I especially appreciate this on those cold Canadian winter mornings, where it's so cold outside the only way I can communicate with other people is through cursewords.
My brother also likes to turn the washing machine on while I take a shower. I pride myself in spending an average of 6 minutes in the shower, to preserve the hot water for everyone else. Not only does my brother do his laundry whenever I step into the shower, but when he gets in the bathroom he's in there a good hour or more, taking a dump then hopping into the shower immediately afterwards. I guess he likes to let the steam infuse the dump smell into his skin and hair...
So yeah, my household pet peeves are, in a nutshell, my dad's crap and my lazy brother.