1. People who leave the label on storage bins. You know, the multi-gallon plastic bins, with a sticker on the front that shows the brand and size. Dude, does it look like that's an intentional part of the aesthetic design? (Hint: it doesn't.). It's exactly the same as the size sticker on a t-shirt - do you leave that on when you wear it?
2. People who refer to the receipt of money from overpaying their taxes as a "tax return". The paper (or digital) forms that calculate your taxable income and tax is your tax return. The money you get when you've overpaid is a tax refund. If your credit card company lets you pay your bill with a tax return ("I'm going to pay off my bill with my tax return"), i.e., a Form 1040 with your information for the prior calendar year printed on it, let me know cause I'd love to do that instead of paying money for mine, too.
3. Drivers who don't bother to park straight within a parking spot. The person who has the reserved carport space next to mine seems literally incapable of not parking at a diagonal. It's not so bad when they park their sedan there, but these are older (read: smaller) carports, so when they park their SUV there, at a diagonal (oh, and not only is it at a diagonal, but one wheel will be touching the line - every single time), it's next to impossible for me to squeeze in between to get into my car.