Why do nice guys lose?

Nice Guys lose because they put others before themselves. No you will not. Youre a winner and youve worked relentlessly hard for what you want. You wont accept anything but victory.

Why does the good guys always win?

The reason for the good guys always win trope is because throughout history the victors write the textbooks, and they always think theyre the good guys.

How can I stop being a good guy?

8:5910:06How to Stop Being a “Nice Guy” - YouTubeYouTube

Does a hero always have to be the good guy?

The protagonist is the hero of their story, but they do not have to be the good guy per se. When in this role, they are often called the antihero. Examples are Now You See Me, the Fast and Furious series, and others where the protagonist is the bad guy.

Why do heroes always win?

The hero wins because s/he gets in the last shot, blow, etc. But in order to make it an even match, the villain has to get in the next to last shot. A story in which the hero first scratches, then wounds, then kills the villain without being threatened in any way wouldnt be very interesting.