I just got tired of it - emotionally, mentally, physically exhausted to my bones of drinking and alcohol and the problems that came with it.
There's other benefits other than weight loss, saving money, feeling better physically, thinking more clearly, and so forth - but you don't see these benefits until you experience them. That's one of the kickers, you can't see how great it is to quit drinking until you make that step - but it is so worth it in the end.
Sober life is not boring - I have an anecdote about that - I was hired to host a local trivia night and was provided with alcohol - I was having a great time! No one else was. They never called me back.