I think this is the third post I've seen where someone speculates that Max likes Mike. It kind of makes me sad that people are so quick to brush Lucas to the side. Lucas and Max aren't as intense as Mike and Eleven, but a lot of kids that age aren't and that's the point. It doesn't mean they don't have a good relationship. In Season 2, Max confides in Lucas about how Billy bullies her all the time and Lucas listens to her and makes her feel better. He is the only person to be consistently welcoming to her (this mirrors how Mike was with Eleven in Season 1) and spends all of Season 2 sticking his neck out for her.

Anyway, I think the relationship between Lucas and Max will be more serious in Season 4.