..unless it was you that put them there. Is this a technique that gives your tracks depth and interest, or does it just make for a mix that lacks clarity? Discuss..

I meant for example something that's so low in the mix that you can barely make it out, or that you can't hear constantly but which is definitely there

whatever noise to fill up the gaps in your frequencies

Well, if it makes a difference (after all, you notice a difference) and the version with the subtle extra sounds better, it's good!

If I finish a song and deleted something I regret later, I always will remember that flaw when I hear the song. Not good!

Hmm. Ok, I guess I was wondering if there's a better way to do this. Should I be mixing/producing so that all the elements of my mix are always equally clear for example?

Hmm, clarity in a mix doesn't mean that everything has to be equally noticable. If everything would be equally noticable, you will have a flat mix. Imagine a synth pad equally loud as your lead. That wouldn't be a great mix. Pads are made to be in the background but that doesn't mean they don't have to be clear. Maybe a pad isn't that noticable but is the mix less interesting if you mute the pad? If yes, the pad belongs in the mix although it won't attract the listeners attention like a lead, for instance.

But thos little extras gives the listener the feeling of 'I don't know why but I like this song'.

I hope that makes sense.

Noisia said in an interview once: even though you may not entirely hear it, it is still there.

It gives out the quality and little extra spice in your mix. But you have to have a good play back system in order to get it tucked in just right.