If Mabi didn't even exist, I'd still be struggling to find my first girlfriend, whether IRL or long distance.
If Mabi closes down, I'd be struggling to stay in contact with my best friend.
Basically, I'd be lonely. Honestly though, I don't care much about Mabi anymore besides making music and friends... and my Scathach, can't forget the Scathach.
If it did close down though, I'd just go back to MapleStory or play osu, maybe force myself to get into League again since I'm like 5 levels away from being able to troll ranked.
If it never existed, then I'd probably be long dead because my life sucks.