There is a Chinese Proverb that says:
“He who asks a question is a fool for five minutes;
He who does not ask a question remains a fool forever”
I've taken this to heart and always try to ask questions in conversations when something is being talked about that I don't know about, and sure enough I always learn something new!
Not asking a question for fear of looking dumb (in conversations) gives you a greater risk of looking dumb if you try to pretend to know what is being talked about.
People love sharing their knowledge and showing off what they know and by asking you are showing humility and essentially you are saying "I respect what you know about the topic and would like to know what you know."
There is so much we can learn from other people! We just have to ask the right questions.