I measure it by how often I'm likely to say "oh fuck right off."
Teeny pop bollocks, I might say it once or twice. Dubstep makes me sick in my mouth a bit, but I'll try to blurt a swear word or two through the chunks of carrot.
I quite like a lot of the charts, mind. I'm not that much of a snob, and the masses do buy into some seriously good stuff. Well, not a lot, they always go a bit rapey in the summer as it's full of... I guess you'd call it dance? House? It's not my thing. But there are a handful of songs that I like. I'd say that's towards the bottom end of electronic stuff, though. I really dig electropop (right from David Bowie and his ilk through to Lady Gaga (!!)), whatever the hell you'd call Prodigy and Pendulum (industrial?), but house isn't my thing at all. So I'll maybe say it at the start of one of those songs, and then ignore it.
I don't like all those American pop punk bands that seem to have the same vocalist. 30SecondsToMars are alright (do they have spaces in their name?), but I'm just as likely to go "oh fuck right off" as I am "this is quite good." It's balanced out a little - bands like Paramore and such, while far from my favourites, have a couple of neat songs and a hot vocalist whose busters are on the internet - but it's far far FAR from my favourite.
Don't like screamo or metalcore. They all sound like the majority of local bands. That or the majority of local bands sound screamo or metalcore. I can't tell. Regardless, I like my music melodic-ish, so if that comes on I'm just as likely to curl out a steamer in protest as I am to just ignore it.
The one that really winds me up though is that BOLLOCKS with the irritating pitch-shifted "duet with a chipmunk" vocals. You know the genre, I think it's called urban, but I most associate it with poor people's ringtones. Rap I can often take; hell, I can occasionally tolerate Beyonce when she's not giving off her insufferably smug vibe. I even like some of Dizzee Rascal's recent stuff... but Akon, Usher, Tinie Tempah (what kind of a name is TINIE TEMPAH for fuck's sake?!). Jesus.
Direct-to-Ringtone, let's call it. What a fucking chunk of smegma. My cat's choked up more tuneful offerings, and I don't even have a cat - the beast I call "Mr. Tibbles" is just a grey sack of cum and Silly Putty that I keep by the telly and occasionally squeeze so that it leaks onto the carpet.
There are exceptions to most genres. Gems, crafted by artisans and genuine creative types who manage to create something wonderful from parts that I'm not typically overly fond of. But I've never heard a ringtone on a bus and found myself thinking "I wonder what that sounds like full-length."