Is it better to be egoistic at work than to be nice?

I imagine people that were so nice at work they let others step all over them. Let them get their promotion, even worse if someone stat pressuring them to resign then they just resign because they spineless while those bullies that pressured them to resign get to stay at their job. Better to be egoistic also so nobody can step over you. I just read a news article about people sleeping at changi airport. I feel like those that are too nice or spineless tend to end up there compared to those egoistic ones or those bullies. We should be egoistic but at the same time be friendly and nice so that we won’t be hatred on and can build connections