First of all, we have personality. Usually people are like, “I’m an extrovert, so that means I make friends easily and love going to parties”, or “I’m an introvert, so I love being alone all the time and hate interacting with people… lockdown doesn’t bother me because it’s my normal lifestyle.” But what about ambiverts? I’m shy around people I don’t know well or who don’t talk to me first, but once I connect with people and feel accepted, I enjoy being around people. Too much silence and isolation makes me feel melancholic. Sometimes I do need downtime, but I also need to socialize with people who like me and that I like as well. So, an ambivert MC would be awesome.
Of course, an MC that likes a lot of the things I do would definitely be someone I could relate to. What kind of music do they listen to? What’s their job? When the MC isn’t at work or school, what do they like to do? I probably wouldn’t relate to an MC that is very bold, fearless, swears a lot, is a thinker instead of a feeler, and isn’t close with their family, because I’m not any of those. Also, what about religion and culture? I think I’d definitely relate a lot to someone who shares my religion and whose culture is either the same or similar to mine. In addition to this, what kind of relationship is the MC looking for? I find it hard to relate to someone who’s relationship goals (including friendships, romantic partners, and family) are completely different from mine.
Favorite things are important and something that isn’t always included, especially with YOU MCs. Even if you are given a choice to pick your favorite out of a list of choices the author gives you, it usually gets a vague response from the character you are interacting with, and never comes up again in the story.
For example, let’s say that the LI asks you “Who’s your favorite singer?” and the choices are: Ariana Grande, Post Malone, Michael Jackson, and Katy Perry. Let’s say I pick Post Malone, and the LI only says “Oh, cool, I like him, too.” And it’s never mentioned again. Now, it would take a lot of work and branching for those kind of choices to actually make sense, but it’s something that could be included as a default part of the MC’s favorite things when creating the MC and deciding what they like and dislike.
Anyway, sorry for the long post. 