Back in high school a (male) friend and I always used to go to a restaurant because it had amazingly good Cajun food, which made it pretty much one of a kind in that area.
The waiters always seemed awfully..friendly. I finally figured out something was going on when one pretty obviously gay waiter said "Have a nice night, you two", and then "I'll see you later, big guy" to me as we were leaving. After that I mentioned it to some friends who were like "That place is like the main gay hangout in this town, didn't you know?!" Uhh, nope.
We still went there, but started bringing along female friends to help fend off the wait staff.