My mains in order and why I mained them
1. Donkey Kong: Donkey Kong 64 was my favorite game at the time
2. Kirby: I thought he looked cool and he played really well, after I started realizing I didn't really like playing as Donkey Kong. I've always been a moderate fan of Kirby games.
3. Mario: After realizing Kirby was pretty cheap, I started maining Mario because I'm a huge fan of Mario games.
4. Bowser: I thought he looked really cool and he's hella strong.
5. Link: After realizing both Kirby and Bowser were pieces of crap in Melee, I mained Link to counter my brother's Peach. This is also when I started getting into Zelda games. I started playing Mario and Bowser less and less, and Link more and more
6. Peach: I've always loved Peach, after beating Event Match 51 with her, I just had to main her. I started playing Link less and less, and Peach more and more.
7. Zelda: After using her in SSE, I realized that she's pretty good and fits my style very well.
8. (currently practicing) Sheik: Zelda turns into her... I feel kind of obligated to be at least somewhat good with her
9. (currently considering) Mr. Game & Watch: After "playing classic with every character" I realized how fun and versatile Mr. Game & Watch is. My friends are trying to convince me not to play him.
The stupidest reason? One of my friends mained Dr. Mario because "He looks like a pimp", and another mained Donkey Kong because "He's the Grand Master"... don't ask.