What he said
In my younger days, I tried to classify and compartamentalise everything, but eventually I realised that I was trying to hit a moving target.
These days, I try to classify music by less stringent things like mood or purpose instead.
When needing to wring a bit more effort out of myself, I play a bit of Led Zeppelin, Accept, Dorothee Pesh, Kiss, Joan Jett etc.
When feeling moody, I play gregorian chant or stuff like Clannad, Enya etc.
When relaxing, very slow stuff like Kitaro, Sarah Brightman, Vangelis etc.
When background "noise" is in order, some Stiltskin, The Jesus and Mary Chain, Garbage, The Primitives etc.
When feeling introspective, I put on some Fleetwood Mac, The Cult, Queen, Pink Floyd etc.
And so forth. Just example bands, plenty more where they came from.