Yep, pet hair and carpet fuzz and human hair etc all get tangled up down there. The little rolling part where the bristles are, it gets wrapped around there a lot and then stops sucking up as easily. Take a sharp knife to the wad of hair and pull it out. Also if you have an old one, check to see the belt is still intact. They break easy and smell funny and make the vacuum not work so well.

I'm exhausted and in between passing out and losing my mind. lol. I need to stop depriving myself of sleep.