Why most people dont like to tank?

[Fendred]

Tanking and healing are things done to support the survival of the team, whereas damage dealing is something everyone does. As a result, the overall survival of the team is in the hands of tanks and healers. It's the added responsibility that causes players to shy away from tanking. It's a classic problem going back to World of Warcraft, and things like duty finder were pioneered in that game as a way to help overcome the discrepancy. The problem isn't damage, because even after tanks were buffed back in "Burning Crusade," people still gravitated to damage dealers. The introduction of the death knight class in "Wrath of the Lich King" showed it wasn't a matter of damage dealers being more aesthetically pleasing than the tanks. Finally, the introduction of dungeon finder proved that it wasn't a matter of people not finding one another either. There were plainly less tanks, and when a solution was added that solved the problem for a moment, many tanks would stop tanking and start being damage dealers.

So the next natural design step in improving the trinity is really going back to Tank/Healer/Controller, but to answer your question, it is the perceived responsibility that tanks shoulder which draws people away from playing them.