If a gate agent is likely to be there 20 to 30 minutes early, plan to do the same.

in the day and age of "quiet quitting" and "only doing what you're scheduled", this ain't the profession to do it.

If I knew an agent would be staffing the door (and my plane would be there), I'd always show 20 to 30 early. In the best cases, I was able to leisurely but thoroughly review the flight, check the plane, deal with any MX issues, etc. Then, I'd have some time to "organize my office", catch up on some emails/day trading, eat a snack or just chat with the crew and say hi to the Pax.

In the worst cases, that extra planned time saved my bacon on more than one occasion. Maybe parking was full so you had to drive to the god-awful back lot and pray a shuttle would be there. Maybe some idiot kid wanted to do mach-jesus on I95, crashes and causes a 10 mile backup. Maybe crew scheduling is dealing with a dumpster fire already, forget to assign a new captain and you have to call them and get the ball rolling. Any number of things can screw you 6 ways to Sunday if you're caught off guard.

On a lighter note, don't be afraid to hang with the crew. I am a relatively young guy compared to most of the captains I flew with. It made me a little more hesitant to see if they wanted to do anything. But I'd wager about 90% of them are always down to do something that isn't 'drink at the hotel bar'. Any time we had a decently long LAS overnight, I'd grab a car from hertz and we'd either hit up some really good off-strip restaurants or visit Red Rock canyon. It was a cost effective way to just hang out (could get a decent rental for ~$40-50) and considerably cheaper than Uber. Plus, midnight taco runs to Taqueria casa after getting off a last leg from hell are the best.