An actual exchange in a group my wife was in, back before we were even dating:
Player: "I wanna catch the stone from his sling! What should I roll for that?"
DM: "Damage."
The "Help" action is so lackluster in D&D 5. I appreciate that it exists that IS certainly a step up. But you do nothing with your turn (not very exciting), and your friend has Advantage, which helps, but if I had a nickel for every time I failed a roll with Advantage, I could probably buy a new copy of the PHB.
(Only a small part of why my game of choice is something completely different.)
Look, maybe he was a paladin of Sune. (Or Calistira, if they're playing Pathfinder.)