Yep, fire hydrants are the main culprit. But once you learn them, you just pretend you've seen them before :) I've also failed to recognize crosswalks. That's

Yep, fire hydrants are the main culprit. But once you learn them, you just pretend you've seen them before :) I've also failed to recognize crosswalks. That's for the most common captchas. When they try to get smart and unusual, it's even more fun. But those are rare enough that I don't remember specific examples.