The most unhelpful I ever received was when I was hiding from voices in a toilet cubicle. "Toothypeg I'm going to tell you something I don't tell many people: after my second DC was born, I developed [long and very graphic description of childbirth injury and resulting continence problems] and I'm telling you this because there's really no shame in what just happened to you, but to suggest that you might want to consider a few spare pairs of panties in your handbag.
I was already so disorientated by the voices from which I was hiding that I didn't know how to respond. I couldn't work out whether she was asking me for advice in dealing with her continence issues (something for which I am completely unqualified) or whether she needed reassurance I wouldn't soil her car.
But I look back on the incident with fondness. She cared: she very much did. And real human warmth and compassion IMO counts for everything.