Whats the hardest superpower to keep secret?

Honestly, I think invisibility would be an absolute nightmare to hide. Think about it, if you accidentally turn invisible while you're out grabbing coffee or just walking down the street, you're basically leaving a person-shaped void in the crowd. People would freak out if they saw a floating cup or clothes moving on their own. You'd be living in constant fear of a sneeze or a reflex reaction blowing your cover entirely.

Telepathy also sounds like a total headache. It's not just about keeping your mouth shut, but keeping your brain quiet too. I bet you'd constantly hear things you weren't supposed to, and reacting to someone's inner thoughts would definitely make people suspicious. You'd have to walk around with a poker face 24/7, which sounds exhausting. At least with flight or super strength, you can hide in a basement or a garage, but you can't really "hide" your own thoughts from slipping out.