Has anyone else noticed that their baby has a deffinate fussy time?

Sebastian seems to to have this period of time between about 5pm and 9 pm (but thankfully not the entire 4 hours) where he is just generally crabby. I know its not colic because he does not cry inconsoleably but rather he just kind of scrunches up his face and kind of "half cries". Thankfully he is easy to console.

He is always happy and giggly in the morning so why does he turn into a different baby later.