Okay there’s two sides to this:
There’s not a lot of purpose to being a fake friend just because you want to be. It’s deceiving.
BUT there’s a difference between professional and childish.
Sometimes you actually need to be “fake” to avoid the stupid and childish drama, whether that’s with work, with school, to avoid physical fights— you actually need to if you want to remain mature. Just don’t talk to them, and just be nice when they talk to you. It’s not hard to be nice, even if it’s considered fake. You might not like your future boss at a job, so do you think you’re going to be flat out rude? It goes the same way with everyone else
But, when you’re fake to get something out of someone, that’s different. Either way, people need to know the difference between maturity and immaturity. Being mature doesn’t always mean being a “fake” is bad. Ever heard of treat others how you wanna be treated? If someone’s nice when you speak to them just to avoid being treated poorly or to potential conflicts, they’re not wrong