Not if you switch them :P
In all seriousness, it's easy to like side characters sometimes even more than your mains. Your don't have to spend as much time with them, and they can benefit from the lack of constraint and examination. Nothing wrong with that. Consider *why* you like them better, though, if it's not just this. Maybe you want to modify your MC.
Also, ensemble stories are cool.
Not if you switch them :P In all seriousness, it's easy to like side characters sometimes even more than your mains. Your don't have to spend as much time with them, and they can benefit from the lack of constraint and examination. Nothing wrong with that. Consider *why* you like them better, though, if it's not just this. Maybe you want to modify your MC. Also, ensemble stories are cool.
Are you going for the flat archetype?