4. Matt Hardy
Is it really any surprise to hear that Matt Hardy had heat with The Undertaker? Mid 2000's Hardy always had a very high opinion of himself, despite failing to live up to his early career potential. Taker had actually been a keen supporter of The Hardy Boyz / Edge and Christian in the early 2000's, but only Edge and Christian really fulfilled their potential. The major heat from Taker to Matt was stemming from Survivor Series 2005. Undertaker came in and cleaned house at the end, but Matt rolled out the ring and avoided taking a bump. He had originally be booked to take a choke slam, but he had told an agent that he wasn't happy with being made to look weak. When word of that got back to Undertaker afterwards, he was furious. He sought out a tape and had it played it back, observing how Hardy avoided him. Taker then yelled at Hardy, asking him if he thought he was above the rest of the locker room. Matt just took the telling off, but his WWE career never really recovered from that night.