I don't usually care if I get overtaken, although, that's probably just because I couldn't do much about it anyway.
However, yesterday evening I got overtaken, uphill, by a bloke on one of those electric bikes (me on my hybrid). I didn't really mind, but I couldn't help thinking that he should be forced to wear something which makes it obvious he's on an electric bike so the people walking on the pavement knew why he overtook me so easily! (although, let's be honest they probably didn't care even if they noticed)... As it happens, I very nearly kept up with him for the next 5 uphill miles anyway, which was nice.
I think it only stuck in my mind because in the morning I got overtaken by a roadie, and he was being drafted by another electric bike. I found that quite amusing because I'm guessing the roadie didn't know it was an electric bike, and was wondering why it was so hard to drop him.