DP recently told me about a video she watched - I didn't ask why - in which a woman used a hairdryer to curl her eyelashes (apparently by putting on mascara and pointing the hairdryer up her face). I said that this confirmed a long-held suspicion of mine: eyelash curlers are the most pointless piece of equipment in existence. You all own hairdryers, right? So they're redundant, even if they had been any use in the first place: I can't speak for other demographics but no straight man ever looked at a woman and thought "you know, she'd be attractive if only her eyelashes were curlier".
She was unable to convince me with reasoned argument that there is anything out there more pointless and less useful. So have at it, MN. I'm betting it won't be long before someone nominates their DH, DP or DC...