There's so many that I'm just going to say MY personal pet peeves, even though they've already been listed.
1) Scalpers, mod flippers and any other jerk out there that buys a hard to get device and sells it for twice what they paid or putting it up "FT will not sell" without even removing it from the container it arrived in.
2) Modders that sell devices that have like a 1volt voltage drop yet will do absolutely NOTHING to fix it even after they've taken three digits of your money.
3) Forgetting to charge batts/ or forgetting to grab a fresh batt on my way to work and having a weak vape after a few hours for the rest of the day until you can get home, where SURPRISE! Somehow not only did you forget to take a fresh battery to work, but you still somehow forgot to charge one too, so even when you get home you STILL don't have a fresh battery!
4) People who own 4 Caravelas, 5 Chi You's, 8 GG's, 20 high end RBA's, and a whole slew of other nice gear who call you down for complaining about not being able to get the mod you want. Oh yeah! You think it's great that US customers can only get a Chi You from Vape Rev do you? Well that's great considering you almost have one for every day of the week!
5) People that smoke that constantly feel the need to tell me how dangerous they think my vaping habit is. "Dude you really have no idea what they're putting in there, or what kind of metal it is your breathing! That stuff was made in some factory, who knows what you're putting in your body!" Oh yeah, I know all the chemicals I'm breathing in. All three of them. BTW, your cig reeks bro..."
6) People who think that the Provari is the top of the totem poll, and there's nothing else that can compare. Sorry to burst your bubble there, but I'll keep puffing my GG+Penelope at .8Ω and disagree with you there! (NOT dissing the Provari, I love it, it's a great device. I miss mine and would replace it if I could afford to mine I lost in my house fire but I wouldn't use it nearly enough to justify doing so)