I always like to listen to happy songs, songs that celebrate the good things in life, as it seems to me there's enough negativity and depression around without having it reinforced in art. (Before anyone says anything, I know there is a legitimate place in art for negative subjects, but they still aren't my favorite).
I think the perky melody suits the lyric well, and I like the harmony in the voices, supporting the harmony between people expressed by the lyric. And like someone else mentioned, sometimes the harmonies are a little discordant, which is just perfect! No matter how compatible two people are, there are always episodes when they don't see eye to eye.
Therefore, an excellent lyric and very suitable melodic setting. My only nit may be 100% due only to me and my limited listening skills... With this subject matter, I think a song should be smooth and effortless sounding, but to me it sounded kind of, I'm not sure how to describe it...maybe "jerky"? No, that's too harsh. It's kind of like an "uncertainty" of where it's going next, a sense of "not sure". Not quite smooth, but maybe "ripply". And maybe that's not a bad thing, anyway.
So, like I said, maybe it's just me, and it really isn't there at all. It does have a fragile quality about it, which I do like.
Vicki