My first character ever created was an orc warrior, got lost in the barrens and when my friend told me they are going to play alliance I deleted that character, rolled a human paladin and did all the fun things paladin did back then, buff, buff, buff and some more buffing with the occasional Reckoning bombing.

Then BC came, me and my friends rerolled horde and I played a paladin again, prot this time, I promised I'd never play holy again, never had so much with tanking in BC, solo tanking Kara and tanking the rest of the raids with relatively no problems.

Wrath came, paladins were the bizznizz but had to heal for 1 week in Naxx because I was slow to gear up because reasons. ICC came, and we lost a dps, I rolled a rogue to fill that spot, was fun topping the DPS meters but I didn't enjoy DPSing so much, rogue was on the bench after that.

Cata release, paladin again up until Firelands, warrior were kings, so rerolled that, Dragon Soul, DKs were kings, rolled that, got bored after we killed DW on HC, quit wow shortly after.

MoP, fuck that shit, not going to panda land. Friends needed a tank for WoD, so started 2 months before WoD got released, paladin again. Was fun blitzing through SoO.

WoD release, pulled an all nighter to get my paladin up to 100, did tons of dungeons, ventured into Highmaul when it got released. Struggled a bit at the start but soon got the hang of it, pulling DPS numbers as tank was fun, nerf happened, I didn't do the same numbers while being somewhat squishy on some fights but we pulled through. BRF got released, paladins were struggling as fuck, but I was adamant, I'm not rolling monk because pandas. Eventually I was close to quitting, wasn't fun playing a class that felt subpar compared to monks, friends talked me into to try a monk. Power levellled the monk to 100, my love for WoW returned, I've never had so much fun tanking as monk, it actually felt like you were doing something to mitigate damage, you had to be reactive, think ahead of the fights and not doing some boring as Seraphim rotation or Seal twisting.

Monk is what I play now and I will never go back unless they change paladins to be of similar style of tanking, active mitigation, needing to think ahead, planning the fight. Paladins will always be close to my heart but Monks are in a different league tanking wise. Blizzard really pulled it off with the monk.

TL;DR Played a paladin mostly through Vanilla to Cata, didn't play MoP because pandas, tried Monk in WoD and loved it. I'm a monk now.