There are some answers that I cannot accept personally. Here they are:
(In alphabetical order)
1) 50s/60s etc.
Like for example, someone says I listen to 70s music. It's absolutely generalizing, simply because 70s wasn't only one genre. In 70s there were genres from Disco to Punk Rock, New Wave and Hard Rock. Where do you fall at?
Very generic. I believe they say it, just in order to show off, and make us believe they don't like Mainstream Music. But don't you know how the genre you listen to is called? What is Alternative anyway? I've even seen stuff like New Wave or Post-Punk being labeled as Alternative, along with Alternative Rock or Alternative Dance. One of the worst generalizations ever. I've even seen bands like Nirvana or R.E.M. being defined as Alternative, when they were more Mainstream than Mainstream, once.
3) Classic Rock
What Classic Rock means actually? It means Rock music that stood the test of time. But people usually refer to 60s and 70s (first half of 70s mostly) Rock-related bands when they say Classic Rock. Obviously, popular late 70s, 80s and early 90s Rock bands might be considered Classic Rock in our days. So more or less it has to do with bands that have been around for at least 25 years.
Personally I find this term very poserish. Just to show off more or less. For example someone who listens to Classic Rock means bands like Led Zeppelin, Black Sabbath and Pink Floyd. But they're not Classic Rock. Classic Rock isn't a genre. This term didn't exist when those bands came out. It's more correct to say Hard Rock, Metal and Progressive Rock, for Led Zeppelin, Black Sabbath and Pink Floyd respectively.
(No, I don't love girls who love "EDM", I just found this wallpaper nice.)
Another common generalization, that is more common in our days unfortunately, than it used to be. EDM stands for Electronic Dance Music. But it's divided in dozens of subgenres. There are heavier genres like EBM (Electronic Body Music) or Trancecore, and lighter genres like Freestyle or Eurodance. So the EDM term isn't definitive at all.
It's impossible. It's impossible to like every music genre from every decade. There are things you like and things you dislike. Otherwise you're just one of those kind of people who just turn on the radio to break the silence, and have no interest towards music.
6) "Foreign" Music
I don't think that's a common term in English-speaking countries, but here where I live, many people call Foreign Music any music that's in English language. Which means any music in English language no matter the genre or the decade. It might be either 50s Rock 'n Roll, or 10s Modern Pop. Do you expect me to understand, what music do you like, exactly?
7) I don't like any music
I get this answer, from gamers mostly. I have no idea why, but it happens. So if in case you are a gamer, then you should be aware you listen to music as well. Most video-games have music within as far as I'm aware. Unless you set your TV's sound off.
But even though, I don't think there's any human that doesn't like any genre at all, unless they are deaf. It's part of the human nature. If you actually don't like any, then I believe something's wrong with you.
8. I like (enter name of Artist(s)/Band(s) here)
Well, I asked you what kind of music do you listen to. Not which Artist(s)/Band(s) you like. Well I'd make an exception if you like the same bands as me though, to be honest.
Metal is divided in way too many subgenres. Like EDM as I mentioned above. Glam Metal is different than Thrash Metal. Thrash Metal is different than NWOBHM (New Wave Of British Heavy Metal). NWOBHM is different than Industrial Metal. And so on and on. So essentially, the term Metal (note, just the word Metal) defines the early Metal bands like Black Sabbath and Cream.
If you don't define, then you make me believe you listen to this crappy annoying Modern Pop of the last few decades. Pop music is different from decade to decade. Duran Duran and Rihanna, were both labelled as Pop. But they are as different as night and day in fact. So keep in mind to define from which decade next time.