What sonic characteristics matter the most?

When you listen to the overall sonic signature of your system which specific characteristics [ timbres, details,transparency, mico/maco-dynamics, imagining/soundstage, prat, low frequency reponse,etc.]are the most important and least important regarding your highest level of relaxation and pleasure of the music you are playing at that moment? I also would be very interested if you GON members would not only share what are your priorities on this topic, but the underlying reasons for these priorities. I think it will be fascinating to see how similar or divergent we are in what matters the most or the least regarding these characteristics in the sound of our systems. Thanks to all who are willing to share.
Tonal balance is of utmost importance to me. If the bass is boomy, the highs accentuated or the mids recessed I can't even begin to listen. Higher mid anomolies are especially bothersome! It seems that when the tonal balance is off I'm constantly distracted by that imbalance and can't fully immerse myself into the music. Psycho-acoustical issues I suppose, a gross deviation from the natural acoustic?
After that it becomes a close call, everything matters and if any specific characteristic begins to annoy I have to fix it.
timbres. It has to sound like the instrument that is being reproduced, in a natural sounding, effortless way. That allows me (At least for me) to suspend disbelief. I can forgive everything else if this is done right. This is why I gravitate towards planars, tubes, and analog. For me, it just gets the "tone" right.
I'll agree with Aroc and add bass done properly which to me means proper weight. Also agree that planars tend to sound more real than cones for accuracy.