I have the exact opposite pet peeve of you--I hate when people try and tell me to wear a helmet. Yes, I realize I'm taking a huge risk by not wearing one, but that's not gonna change my mind. I wear them on young horses, or horses I don't know well. But for everyday riding, I choose not to. And that won't change.
I also hate people telling me how I *should* be training my horse. She's coming along just fine without your help, thanks, so I'll continue to do it my way. Unless you have a valid point, which I'll take into consideration.
People who think they are all-knowing. Oh, you've been riding for a year and a half and can canter? Good for you. I've been riding for 13, used to show, and have successfully started many youngsters under saddle. I have a feeling I know more than you, and I don't want your opinion, thanks. Unless I ask for it, which I probably won't unless I KNOW you're more experienced than I am. So don't waste your time.
When people tell me my horse is fat. Yes, I know. Yes, I'm working on that. Now move on.
SHARKOnline (youtube channel). They just need to go away. Along with everyone who attacks rodeo/racing/saddleseat/jumping/dressage/anything without proof to back up their argument. You all are idiots and don't know what you're talking about. So stop.
I have more, but I need to go to class, so I'll stop now.