Oh, I get that. It frustrates me to no end. I have my share of matches like that, but they're far and away not the majority. The key there is to literally stop caring once you get past a certain point--either surrender vote or concentrate on doing something that's funny even when you fail.
RE: ARAM. I don't know. If things fall out right and the team comps are balanced, it can be fun, but an unbalanced comp completely ruins the match, and too many are roflstomps where one team has a clear advantage, presses all the way to inhib, is briefly beaten back and wiped when they get cocky, and then comes back for the win. The obvious upsides of ARAM are that you get a lot more action without having to worry about CS, and that you get experience across a wider range of champs.
Don't get me wrong, I enjoy it, but I like standard SR more for a couple reasons, the greatest of which is that ARAM doesn't really offer much opportunity for thought or planning. It's literally just basic teamfight tactics: Don't focus the tank, kill the carries and nukers first, don't be a moron. There's no potential for anything akin to roaming, ganking, stealing buffs or objectives, split-pushing, etc., which is admittedly by design. The closest I've had is passive-stealthing as Teemo, waiting for the enemy team to pass me by, and then grabbing a bunch of kills when they retreat after barely winning a teamfight.
That, and instead of there being a complex relationship of interactions between champs, you've got a handful who are godly in ARAM because of the nature of the map, a handful who are godly because they've got heals/natural sustain, a bunch who are mediocre, and some who are practically useless because their playstyles don't match ARAM. I will admit, though, that this week has made ARAM markedly more frustrating because half the matches are full of hookers. Er, Thresh and Naut, that is. :|