Not finding out gender and people's opinions

Ok, so when you don't find out the gender everyone is constantly telling you what you are going to have. Like flat out telling you it's going to be this or that. My midwife yesterday said, I'm sorry but it's 100% a boy. This was solely based on her listening to the heartbeat.

I just want to know if anyone else has had this? What were people's experiences with not finding out, were you surprised at the birth? Did you get a lot of people say it was one gender and not the other? I found out what I was having with my first so this experience is very different!!