The struggle to fit in follows everyone throughout life. It's one of those human experiences everyone must endure.
In school, you don't want to be the kid playing alone during recess.
At a party, you don't want to be the only person standing in the corner with a drink in your hand and a sad expression on your face.
In the office, you'd like to have people talk to you during the day. Or at the very least, not actively dislike you.
When you put groups of people together, not everyone is going to be best friends. Even if co-workers aren't fighting, one person can feel like an outsider and grow to dread heading into work each morning.