Honestly? It truly depends.
Movies I'm super early for. I want a good seat, I will get there 30 mins or more before the movie starts. Pretty much any important event, I get there on time or fairly early.
If I'm just going over to someone's place, I get there when I get there. You say 6, I'll prob be there by 6:15 at the latest if it's something like a board game night. Video games? I'll be there when I get there but no later than 30 minutes after start time.
I used to be very punctual, get there right on time and leave right on time. Then all the people who weren't punctual would get there late and I'd be standing around waiting. So I don't get there on time anymore. We're having dinner at 6, I'll start getting dressed at 5 till and leave a little after 6. I'll still beat everyone there 9 times out of 10. I want to actually sit down by 6:30 or 6:45, I tell them to be there at 6. I had people over last night, and everyone always shows up 2 hours after start time if not more. I tell them 8, they show up at 10...I told them 6 on purpose so they showed up at 8, and that was the 2 out of 6 that decided to actually show.