I was new to MMO's when I started FFXIV and had little clue as to what role to pick. I went with Archer without knowing about what each class was supposed to do. I knew nothing about what enmity was either.
I enjoyed it but decided to give Conjurer a try. I enjoyed it a lot. I liked DPS'ing with the heal class and reposing mobs in earlier dungeons. It was the first class I've gotten to lvl50. I did some end-game with it and got my Relic weapon, when I decided to give the tank class Gladiator a try.
I like tanking more because I'm better at it than the others. I use PS4 pad and this class suits it a lot. Healer takes up a lot of slots with different macros etc. and I have to switch between 3 slots to utilise them all. At least with PLD or WAR I only need to use two. I think I'm just a better fit tanking compared to the rest.