Can be a mount, a transmog set, a piece of gear no longer obtainable, a rare item from vanilla, a toy, a pet, title, you name it!
I’m super proud of my Infinite Timereaver because it’s such a rare drop, and Invincible. The latter isn’t as rare anymore but I’m still super proud to be it’s owner.
Herald of the Titans is the title I’m most proud of
Honorable mention: Tabard of the Argent Dawn.
For me… it’s not a reward in the game, but when i proved to myself that i could go from super casual LFR/Normal raid clear max, to getting CE.
The game didn’t stop me in anyway, or some elite cabal that some forum users are so fond of.
If it has to be an ingame reward I’d say Rhok’delar that i got on my hunter back in vanilla.
That is impressive, gratz! I used to be a mythic raider a few expansions ago but my time constraints limited me in how much I could play. These days I strive to reach heroic clear and ilvl, and that’s enough 
Thanks, i raided a lot in vanilla, and then as you said time constraints… but at the end of Legion i decided i wanted more now that i had the time. And by BFA S2, CE…
Felbear because it’s so cool. Perhaps the Horde bike if I could use it on Alliance.
cant be proud of anything in the game anymore, they made it so easy to get things like mounts or titles. i have so many of them i dont even care to call them prestigious
which strangely makes it easier to not play the game
if you had asked me a few expansion ago i might of said something like getting the auction mount or getting 2k rating or a title
but honestly, no1 and i mean no1 cares about this stuff anymore, with all the boosting and wintraders etc. everything lost its value
Dragonwrath, Tarecgosa’s Rest, my first legendary weapon, having done the entire (incredibly long) questline solo during WoD. It’s probably the hardest thing I’ve done in WoW.
But it was worth it for Stormwind being mine just for a few minutes.
I managed to actually fulfill a public crafting order
I know this is personal but I disagree
Until a few weeks ago I didn’t even play retail, I was a Wrath-Classic player but I got tired of the raidlogging and decided to run a few older raids on retail for some mounts, without high expectations I might add.
In one week’s time I got: Invincible, Gul’Dan’s Mythic mount and the Infinite Timereaver. This more than anything brought me back. The true endgame in wow to me is transmog and collecting mounts, and the recent drops re-invigorated my drive.
For example I decided to lvl and play a priest at max purely to obtain the s2 transmog set. Looks gorgeous imo.
Although it’s nothing special, but for me it’s the violet spellwing - mount. It’s a nice memory for my first AOTC since I play this game. 
I was going to say something similar. It’s how much I’ve improved as a player rather than some pixel-stuff I’ve obtained.
I’m a former solo/world content player who came back to the game in BfA after several years away and went from complete dungeon beginner to KSM to getting teleports, from first setting foot in a raid (got carried to AOTC so that doesn’t count) to 7/8 mythic this season with my guild. We’ve got a strong and enthusiastic team now, and a lot of us are keen to push for CE next season (even though the more experienced officers are clearly wary of putting too much pressure on us).
Sure, my Tyrael’s charger is cool - or it was until everyone got one LOL - but it’s the stuff I’ve done rather than the stuff I’ve got that I feel proud of.
This so much, and as cliche as it sounds, the friends you’ve made along the way… It does feel really good that you can take a few months break from the game for w/e reason, and when you return you have friends inviting you to groups right away ect.
Nvm jumping into other games with them 
Congrats indeed. As for the “big evil elitists” and all that 
. A person with 3 kids, 2 jobs will be able to organize his time and be a mythic raider if he wants it.
Ofc if somebody doesn’t to raid in the first place then he will hide behind “I got a life!” or whatever 101 already heard excuse…
This so much, i got my CE even when i have 100 travel days per year on average where i can’t play… Its why it means so much to me, it’s not the CE itself, or the titles… but proving, at least to my self, that all the excuses we hear all the time are just that. Excuses.
I am definitely most proud of my headless horseman mount 
got it on my 37th ever attempt and it was the sweetest mount drop ever…
If you know, you know 
I am most proud of my Infinite Timereaver
It took more years than I’m willing to admit, and basically became an obsession, but managed to get it
…and to be honest, never used it since
So maybe the Professor and te Chef titles , both required hard work and I use them!
i got the chef title last week 
outland never dropping them recipes
That kind of happened to me IRL.
I don’t work full-time hours because I don’t need to. When DF came out my workplace was really, really busy so my boss tried to get me in full-time at 1.5x pay, I refused on the grounds I was “Busy those days”.
I don’t raid though, but I do care about WoW (as a whole) more than my job.
Getting the server top rogue proving ground record back in MoP.
I remember the top was a rogue at round 94, I beat him at round 96, was super fun to squeeze out every ounce of skill I had to reach such a round, and almost an hour and half each try was stressful, but seeing my name at the top was worth the effort.
Honorable mention: I had world top 4th/5th rogue logs on dark shamans back in the day, felt really cool.
Is it really that rare?