Discussion What's Your Biggest Tourist Pet Peeve?

This isn't specifically about any particular tours, but about tours in general. I've discovered a pet peeve of mine when traveling with groups: people who are perpetually late, holding up the entire group. It's frustrating when you're excited to explore, and someone's lack of punctuality cuts into your time. Does anyone else have a tourist pet peeve that drives them crazy? Whether it's loud talkers on buses, people who don't respect local customs, or something else entirely, I'm curious to hear what grinds your gears while traveling.