White Pines, the way they goober up my rope and buckstrap. Try slideing your prusic one handed over a 1/4" glob of gooey Pine sap. Pin Oaks suck to but they are actually easy to prune, it's just that they can be so ???? frustrating, the way the limbs just refuse to hit the ground. In the same vein, Pepridge have the exact same trait, but here in the Northeast not quite as common. Honey Locust that have big nasty thorns. In the previous response to this one Eric posted a picture of what appears to be a little baby Honey Locust. Just imagine what there like when they get large...Nasty!
Also any tree covered in either Ivy or Vines. I can't decide which is worse. Vines make you trim not only the limbs but the Vines as well to enable the limbs to hit the ground. God forbid you need to rope the limbs. (I did today and it sucked) Or Ivy, Hiding all kinds of unforseen problems. Insects, animals and worst of all, hidden tree defects. I'd have to vote for the Ivy strictly for the hidden defect issue.
Thanks for reading...
T