Ask HN: Pet Peeves?

We all have them -- sometimes legit and sometimes not --, and we usually like to talk about them.

Let's have a mutual sound-off. Why? So we can learn. Oftentimes a pet-peeve is really a legitimate concern (or even a breaking of rules or laws).

My pet peeves?

    1. Sloppily white-spaced code (First programming language was python.)
    2. It's vs its, (etc.)
    3. People who don't use turn-signals.

What are yours?