After having played Tanks and Healers in another MMOs I realized something: as a Tank/Healer I was never playing the game I wanted to play; I was always stuck playing other people's game.
"We need you to come tank/heal <this>." "But, I'm busy doing <that>." "Oh come on, you can do that anytime
you want. We need you for <this> now."
The problem was that as a tank/healer, "anytime
" never happened because someone somewhere always needed me to do what they wanted to do.
So with SWTOR I've gone DPS. On all my toons: Vanguard, Sentinel, Gunslinger, Assassin, Mercenary, Juggernaut, Sage (almost 50!) and Operative (sitting at 19).
It is fun to do what "I" want to do for a change.