I AM SHOL

I might need someone to explain to me the mindset of a greedy salesperson lol. I just witnessed a coworker leave a client they were helping for a celebrity client in a heartbeat while also keeping credit for the original client. Is that the whole goal of a salesperson? How is their way of thinking when it comes to that? Am I the weird one for not being so aggressive and sharky? What is it really? Lol *shrugs shoulders*