Do you ever look at someone and wonder what they are thinking ?

Is there ever a time your looking at someone wonder what they are thinkig ? Or in conversation with someone and in the middle they just stop and its silence, does that ever make you wonder whats going on in their head ?

Yesterday I was laying in bed with my boyfriend and we were talking, the conversation went flat. He was looking at me so I asked him what he was thinking about. All he could say was, “oh nothing.” But that made me wonder what he was thinking.

Do you ever do that ? Or am I just completely weird. ?