It is absolutely critical to good mental health and having healthy coping mechanisms for stress.

Social support structure doesn’t necessarily mean staying out all night drinking and partying with your friends like a college student. It can also mean spending quality time with your family, neighbors, and acquaintances that you share hobbies and activities with.

Life is a series of endless choices.

I recently ran a 24hr relay. There were absolutely those who drank/partied while they participated. They posted slower times and probably slept less. I didn't sleep as much as usual (because I was waking up to run every 6hrs), but I slept more, didn't party, ran faster than them.

Neither of us was right/wrong in our choices. I would have felt like crap if I had their habits, but maybe it doesn't affect them.

Not sure about that. A few social activities are negative (nightlife, eating out maybe), but most seem to be neutral to me (hanging out, gaming, religion), and it's pretty easy to find positive activities (walking/hiking, sports, climbing).