i think one of my favorites(its happened more than once) is when you see i cant log in/remember password etc on a windows box. see 30 posts from "experts" giving either A insane work arounds, or B something that will never work anyway. Always love to pop in and just go "ERD disk". watch 30 "experts" facepalm.
or...just in general tech support, latest one was needed a new wireless router/modem for home because the one we were using was dropping packets intermittently. So i call tech support...get the normal BS(reset it, check connections etc)...yes ive done all that i need a new router the wireless is failing...uhhh are you sure? yes. Uhhh i dont think thats it. It is, just send me a new one. (5 more minutes of this....) ok were sending you a new router. Lo and behold not one dropped packet in over a month. its MAGIC.