Luck

Luck is a big part of WoW. Obviously, for some things no, or little, luck is required. For example I got my "The Diplomat" title 2 days after patch 3.0.2 went live after I finished grinding exalted rep with the Timbermaw. This required little luck, just the ability to grind.
Same with the exploration achievements I finished yesterday (only Northrend left :)) - there was no luck there, just the time needed to run around.

However as part of my exploration I had to go and discover Orgrimmar. Since I was already there, I figured I would go inside and do the Ragefire Chasm instance for the Achievement. Took quite a few deaths but I finally made it. By the way, Shattered Barrier was increadible, really helped a lot. Every time I would rez I would first of all put on my Ice Barrier. Quickly I would have a bunch of guards on me, hitting me like I was aiming to kill Thrall or something ;p Ice Barrier would quickly break and poof - suddendly I'm running alone, leaving all the guards far behind me :) Invisibility was also my friend :)

Anyway once I did the instance I figured as I am inside Orgrimmar why not catch a fish in order to get The Fishing Diplomat achievement done. So I ran a little more to the closest pool (another 2 deaths), fished a single fish and got it. Well, as I was already in a pool, in Orgrimmar, with a fishing pole in hand, I figured - why not give it a go and try to catch Old Crafty! He's also needed for an achievement! Alas, I did not have any luck - first I spent 30min fishing without catching him, then a horde hunter decided it would be fun to gank me and that pretty much put an end to my fishing.

So in general I much prefer those things in WoW I can get done without depending on luck. Usually, I simply don't have luck :(

However, last night, to offset the disappointment with Old Crafty, I got very lucky indeed. I went to do the Headless Horseman with some friends. Didn't even plan on doing him last night, we wanted to do some heroics, but all the Outland instances were bugged and could not be entered. So we decided instead to do the Horseman. As all 5 of us had not yet done him, we could summon him the full 5 times.
The 4th time, The Horseman's Reins dropped. We all rolled need, and I won! Talk about lucky, first I got lucky the item even dropped, then I got lucky by winning it. Soon after I had the Headless Horseman's Mount in my mounts window and when I summoned him after porting to Shattrath I was blown away - a flying horse is very awesome :)

So I dislike depending on luck, but when I do get lucky? It's awesome :)