Assassin's Creed Brotherhood. Most frustrating game I've played in recent years, and NOT because it's difficult (it's a cakewalk). Much of the game involves escaping groups of armed guards, except you're so adept at combat/countering that these fights are
always a pushover, so the CONSTANT hassle you get from these guards proves to be a perpetual, eczema-like irritation rather than a challenge, just time-consuming events with no reward whatsoever, had me swearing at the screen in pure ANGER, with an ire I've not summoned in eons(!!!!)
Also, the f*cking
horses. Again, you'll either be (boringly) tailing one of your assassinees or escaping guards, and your horse - which can easily leap over fences and the like - will get stuck on 1-inch high 'steps'/ridges on the landscape, necessitating a round trip to negotiate what are essentially piddlingly small steps for even a midget, nay a *baby*, even. This is
f*cking frustrating. Truly.
Then you're just plain trying to RUN from guards...so your bloke grabs a building, and hangs there for a bit...while the guards are getting closer and closer...and you press 'B' to drop, and it doesn't respond straight away...and you've got to spend a good two/three minutes killing the ten or so guards that've been chasing you...and this happens ALL THE TIME...aaaaargh!!!
AND, don't get me on how easy it is to be on a very small building, want ot simply drop off, yet somehow you'll jump and mash your health down 50% because the controls simply are TOTALLY FLAWED and BARELY INTUITIVE AT ALL. Ug-auch,ach.

In fact, the whole thing is a big thing with lots of small and medium-sized things to do, yet none of those things are of much - if any - substance. I've spent a whole
fortnight doing AssCreed 2 & 3, more fool me!