Having a strong "inner ear" is very valuable indeed. When you are playing music, there's a set of instructions being thrown at you to respond to. For starters dynamic level, tempo, and meter is to be considered. Let's talk about these elements.

Dynamics

What makes a good conversation? Subject matter obviously is the most important thing, then the ability to elaborate with a certain amount of knowledge and panache. Rising and falling tones of voice can control the conversation's flow, and music is no different. Paying attention to the dynamic landscape helps assure a congruence within the sound; When the music is asking for hushed tones, then it's probably a good idea to be sensitive to that request. But..when it's time to scream, let it loose! However, most people I know don't like to get yelled at so being mindful of your "tone" can really be an advantage for you.

Tempo

Tempo is the pace at which the music flows. It's like a cadence, a march, a pulse that drives things along. It's the heartbeat. And just like the human heart it's pace varies slightly in places; that's emotion entering the picture when the pace ebbs & flows. Because of the advent of machines, Disco (yeah I blame that bitch), and standards placed upon "modern music" by a coked-up record exec obsessed with perfection, emotion was somehow put into the sidecar and left to rot. I got news for any of you that think it's the drummer's job to "keep the time". BULLSHIT. It's everyone's job to keep their own time! Besides, "keeping time" is a static activity; it's as mundane as assembly line work and that's NOT why I started playing drums! Play music, not keep time.

Meter

Meter is the flow in which the music falls; in the big picture, it's going to be either duple or triple. Either you will play "square" duple pulsation (straight eighths for instance) or triplet (swing time feel). When you break rhythm down to it's most basic levels you'll find that it's only groups of 2 and 3! If you're playing in 3/4, 6/8, 9/8, 12/8 time signatures then more often than not you're in triplet meters. When you play straight 16th notes, that's a duple pulsation. It's very important to consider the meter of the songs you are playing, especially if you are creating a setlist for the band! All too often the key of a song and the tempo are the major considering points for "what's next" and many bandleaders are completely ignorant to the fact that yes, we just played 5 shuffles in a row. For drummers this is a real wrist-slitter. I didn't have to say that, but it's on my mind and it's important to know.

I'm All Ears

On to the inner ear concept. When you "hear" a song in your head that's a great thing because you can "listen" to it and play accordingly. It's the music inside that emenates from you, whether it's your own music or someone else's. Non-musicians exprience this as well in that the songs that are ubiquitous (play Freebird!) can easily be accessed through memory and sing-alongs (picture a room full of drunk college kids singing "Thriller" and get back to me....So as a musician, it's paramount that you get ahold of this concept and put it to use.

Hearing the song from within will not only give you a stronger framework to draw from but also physically you can benefit; It's akin to "slowing down the baseball". It's a natural "lead-in" that makes you flow. And it's with such ears that I am able to create the sandcastles made of air that I'm able to spin off. It's good that someone was there to capture the moment!