I was about to fucking snap my 3DS in two, I swear to God.
Oh, you first? NOPE! Blue Shell, red shell, next guy hits you with a star and knocks you off the track.
Good GOD this game is good and addictive but frustrating as all hell.
I don't mind being fucked over in multiplayer/online, but I also nearly snapped my 3DS a few days ago when playing through all the cups in single player. There was one cup in particular that I had to attempt four times because I got fucked over by blue shells or other items.
People can complain all they want about the rubber banding in Mario Kart 64, but I thought that had the most fun single-player in any Mario Kart, on account of the opponents never used certain items, including red and blue shells. The rubber banding was to compensate for that, and it was a much less frustrating way of keeping races close.
It's also worth noting that Mario Kart 64 is the only Mario Kart game where you aren't required to play single-player to unlock anything, which is always a good thing in a multiplayer-orientated game.
Fortunately, the online in Mario Kart 7 is absolutely outstanding, so I'll never play single-player Grand Prix again.
I'm really happy with Mario Kart 7. It's basically Mario Kart DS, but it fixes all of it's faults (no snaking, you can hold items behind you in online, all of the tracks are playable online), and has some of the best tracks in the series (beaten only by Mario Kart 64, in my opinion).