If you want to find out who someone truly is you have to spend lots of time, in many different situations. The problem is that if you’re always around someone when you’re having a good time, you know how they act when they are having a good time. How about when they’re stressed? When they have to work hard? When people say things they vehemently disagree with? How about on the internet? Do they feel pressured to act like a goody two-shoes around you? Or are they just being who they really are?
I think we can be surprised by how different people can become after first impressions. Just because we never really knew them in the first place.