This doesn't actually belong here because I did in fact comply, but it really chapped a certain portion of my anatomy that shall remain nameless.
I'm one of two people who answers an email help-line for my county library system. Got an email today from a guy who had a problem that turned out to be a bit of a head-scratcher. Nothing big, just "Huh. Why'd they do it that way?"
I responded to the guy's email and explained things and pointed out his options, including one or two he'd probably need help with. So I went back to work but made a mental note to check that email again before I left work.
He had responded. Or rather, his email provider had responded, with a form letter explaining that the gentleman I had dared to email was not willing to accept emails from just anyone. No, he had standards, and if I wanted him to respond I had to hie myself to the provided link with hat in hand and give a darned good reason why the gentleman should condescend to grace me with a reply. I'm willing to concede the remote possibility that the actual email contained slightly less scorn, but you get the gist.
If it had been a personal correspondence I would've just ignored that email and the guy could wonder why he never heard back. Given that it was part of what I'm, y'know, paid to do I held my nose and filled out the form. Under "Why should I read your email?" I wrote that I was responding with help and advice that he had asked for. I left off, "You knob," but it was a close thing.