Music has this emotional thing to it, and it touches people in crazy ways. The power of having that power is something that, once you have it, you don't want it to ever end. ↗
I personally take cues directly from the script, then I like to surprise the other actors. But you must maintain control on a level and see how far you can go up, down or out emotionally. You have to balance the craft with spontaneity. ↗
Of course, I have the emotional ups and downs of pregnancy, like crying jags for no reason and then the next day I can't even remember what I was crying about! ↗
You can go crazy and play solos in the right place, and that's great because it can intensify and bring an emotional lift. But the thing is you don't want to get in the way of the song. ↗