What is Plain Bagel?
1.
Someone who has no "stand out" features and who is boring as hell--just like a plain bagel--no cream cheese, no jelly, no sesame seeds, NOTHING.
Anthony: Are you inviting Janet to your birthday party?
Yvette: Yes, why?
Anthony: Ughh! Don't invite her! That bitch is such a plain bagel! She'll suck the life out of your party.
See