I had some wacky luck this year.
All weekend my dreadnoughts were great and not only survived games (unusual for them) but got pretty good at busting open vehciles.
My Grand Master was amazing at shooting things (especially enemy vehicles) - but consistently failed armour saves all weekend.
The best example of this is my tau opponent fires a burst cannon from a crisis suit at him on the off-chance of doing a wound.
All shots hit, all shots wound - I roll a handful of 1's. Nice.
I might have been more upset were I not losing by miles anyway, so instead it just seemed funny at the time. (My GM obviously learned that lightweight cardboard is no replacement for ceramite, no matter how much the weight saving helps with the disco moves)
The other wacky thing from the weekend for me was my 'Emperors' Tarot' wargear which actually hurt me all weekend, by costing me the first turn in 4 of my games (Yes - I was unlucky enough to get -1 result to the first turn roll off, and when that came around, I rolled the same or just one higher than my opponent, which after all rolls were sorted then resulted in my losing first turn 4 times in one weekend thanks to that one piece of wargear.)
The tarot then made no difference to the result in the other two games where I did have the +1 (i.e. the first turn dice rolls were so far apart it made no difference.) So in essence, I spent 15 points to handicap myself for the weekend - what a buy!