1. If I don't lift weights and occupy my time with disciplined habits, I will probably be out comitting random felonies all day long. I think most men need some sort of physical outlet to "get the war out of them" if you will.
2. Halo effect. People treat you better when you are jacked in almost every context, but particularly with girls of course. This is inspite of how much they proclaim a love for 'dad bods'; what girls say they like and what actually creates involuntary sexual arousal are two different and often opposite things. But even in a professional context it feels like with the exception of one fat short gay boss, most bosses let me get away with way more shit that other employees wouldn't get away with and I'm sure some of it is subconscious fear of pissing off the jacked bro. You can also "get away with" just being nice and nobody fucks with you; sometimes being "too nice" and agreeable is an invitation for people to fuck with you but if you are jacked suddenly it isn't.
3. I enjoy competing. It gives my life structure and those periods of deprivation put life into perspective and make all of the simple pleasures easier to appreciate and enjoy.
4. Girls love the novelty of fucking a jacked lean guy even if they later find out its not their niche. They usually at least enjoy trying it out. Like guys enjoy trying out a girl with fake boobs or anal. Jacked lean guys are much more rare in the country where I live (and fake boobed girls are more common)
5. I feel healthier and stronger throughout the day and I think the way I'm handling my PEDs, cardio, training, and eating is overall life extending. Remember, juiced up NFL players have like 1/3rd the all cause mortality of a typical American male. There's definitely a point where you can take things too far with enhanced bbing, but there's also ways it can be done where you are still overall healthier than the average person.
6. I'm a high school teacher in a country where lifting is still fairly niche among the general population and just being a lifting guy myself I'm acting as a role model and getting kids to take up a fun, healthy, habit that can improve their lives in a lot of ways. A lot of former students who have graduated have gone on to do men's physique, powerlifting, and football. I'm proud I was the guy to teach them how to ATG high bar squat and bench press and got them both inspired to start and taught them how to do it.
7. The discipline I've developed in my lifting career has helped me in other parts of my life. I'm so used to going to the gym even when I don't feel like it or eating 95/5 ground beef and rice when I want a burger and fries that it suddenly becomes easier to go to work or write that boring pointless paper even when I don't feel like doing it.