I likewise can't stand supporting kalista unless it's one of my friends, I'll know how they'll use her reliably enough I can work around the annoyances and make it functional.
But aside from that, I hate supporting ezreal, if he falls behind he's basically useless; he can't shove waves, unable to farm fast, and his kill potential is pathetic outside of teamfights. However that's not the most annoying thing about supporting ezreal, he's such a chore to protect as most players will blink away from their support, even if it's a braum or someone else durable enough to bodyblock the ditch effort attacks; this goes for lucians & vaynes too, how do they expect to be protected when they flee from their teammates?
Marksmen I enjoy protecting? Probably have to be jinx, twitch & jihn; they can provide enough crowd control to cover for themselves when you roam (or to ensure a kill if the enemy negates your setup), can still be noticeable threats even if behind, and still have plenty of pushing power if/when the team needs it.