Do you know when you have body odor?

I take a shower every other day in general. Today is a shower day. However, I haven’t had the AC on for most of the week and the humidity has been pretty high.
I went to Subway and when I raised my arm to point at something body odor wafted up at me. :O I slammed my arm down and acted like a T-Rex when I picked up my food.

How is it some people seem unaware of their own strong BO?