It's so insane to me that someone can be described as a bag hog for bringing a backpack and not wanting it to obstruct their leg room by people with huge roller bags that take up half a bin on their own. These kind of complaints feel like the rock bottom for self awareness.
"How DARE that person want to use some of the communal storage space offered to all of us? They should have known I'd be bringing my giant roller bag and would thus need more than 1 passenger worth of bag space. How could these people not realize I'd need that???"