Being good and being nice are two completely different things. The two are often wrongly conflated. You can be good without being nice, and you can be nice without being good.
"Nice guys", for example, behave the way they do only do so to get pussy. They put on this sycophantic, acquiescent faccade to please m'lady just to get a whiff of that rank roast beef. But they will shit on, humiliate, and even assault, their fellow neckbeards to protect m'lady's honor and be in good standing with their queens.
A good guy, on the other hand, is a man of morals and principles, honor, and possesses a spine. They'll do and say the right thing, regardless of it being seen as "nice" or not. They can be aggressive and confrontational, both verbally and physically, but they will not be in the wrong. Their displays of hostility are justified. They'll be standing up for themselves, defending their family and friends, and never bullying the weak.
Lesson's over, boyos.