Forgive the content of the text.
The expressions below simply check the velocity of your animations in AE. If you move an objects motion ends abruptly (ie: you didn’t easeIn @ 100%) the physics will kick in automatically. It’s all just that stranger than fiction crap. The paragraph uses text animations (although it’s easy and i could have made it a plugin, it sucks because it’s harder to get words to just appear as opposed to fading in and out with the swings). Anyways, not for paragraphs and the proof is in the video. The code for the rest is below. (Dr Gonzo in the comments below tweaked the code and it seems to work for everybody)

This is code for bouncy position movement.
Just paste it in the position expression field, in this case it will affect x, y and z movements:
// Inertial Easing (elastically reacts to the speed at which it was animated)
n = 0;
if (numKeys > 0){
n = nearestKey(time).index;
if (key(n).time > time){
n–;
}
}
if (n == 0){
t = 0;
}else{
t = time – key(n).time;
}

if (n > 0){
v = velocityAtTime(key(n).time – thisComp.frameDuration/10);
amp = .02;
freq = 3.0;
decay = 5.0;
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{
value;
}

And this is tweaked a bit for rotations… paste it in the x, y or z rotation. It will only affect the ones you place it in:
// Inertial Easing (elastically reacts to the speed at which it was animated)
n = 0;
if (numKeys > 0) {
n = nearestKey(time).index;
if (key(n).time > time){
n–;
}
}
if (n == 0) {
t = 0;
} else {
t = time – key(n).time;
}

if (n > 0){
v = velocityAtTime(key(n).time – thisComp.frameDuration/10);
amp = 8;
freq = 2.0;
decay = 3.0;
value + (v/100)*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{
value;
}