Another candidate for the Worst Gambit is the Lithuanian gambit... (another black gambit)
You're basically trying to play the King's gambit with at tempo down. If your opponent just plays normal moves, you "might" get an attacking chance, and those checkmates are very sweet...
but usually you don't
Englund Gambit... It's addictive like any gambling... but if your opponent knows what he's doing, your development will suffer