Alright kiddo, let me explain "need for affiliation" to you.
You know how sometimes you really want to play with your friends and be around them? That's because you have a need for affiliation.
Humans have a natural desire to belong and have relationships with others. This is called the need for affiliation.
People feel happy and secure when they have strong connections with others, and they feel sad or lonely when they don't have those connections. So, it's important for us to surround ourselves with people we can relate to and who make us feel good about ourselves.
Does that make sense to you?