Why are some tunes louder on one side?

[sn0wday]

At first, I always thought hearing this was like an error on the part of my headphones, my ears, or the file itself.

But i'm noticing it more lately and it's definitely the song itself. I'm sure plenty of you have heard tracks where the bass is more on the right or left and it just feels really uncomfortable to listen to.

Some examples...

http://www.youtube.com/watch?v=XkdYSj_Er7I All on the Right.

http://www.youtube.com/watch?v=JH7i80uoXuw On the left, especially at 3:58 onwards

http://www.youtube.com/watch?v=VCmcKcD9pc0 If you've got the non-youtube version floating around, it's more on the left.

Is this all stylistic? A reason? Error?

[Reamz]

Doesn't seem like a major problem to me. A lot of this music is mean't for clubs as well. Stereo effects in clubs won't make that much difference. Just gives more space in your tunes

[MKRUGGER]

I didn't listen to the tracks, but I know what you mean!

This bugs me so much, in every genre of music, when certain elements are panned too much to one side.. Just makes things feel awkward and uneven :/