If he has good trades, I TRAP him. If he has bad trades, I SLAP him. Then he turns invisible, but I still kill him. Then his Llamas spit on me, sooooooooooooo I kill them as well. THEN I HAVE LEADS!! :D
They are annoying for the most part, I don't kill them anymore. I used to due to they're crappy trades. But I just turn them of in the Minecraft Gamerule Mob Event.