http://www.fileize.com/files/70ba8d18/d0a/Trololo.swf <<< First animation I did after not animating for 3 years. Any thing I can do to improve an animation overall?

So, Im just commenting cuz I loved Clannad, but here is the deal:
U should study how an object reacts when hits the ground, that Trol box wasnt very realisitc u.u

True, the box should have bounced slightly to the side and suspended for more time, then have come down and slid until the opposing force of the floor stops it's descent.
Keep practicing.

Well it seems like you used the box as a cheap novelty in order to cut your animation short without actually finishing it. Even if it is, you could've put more work into the collision.

edit: (not in a very good mood, sorry if I'm an ass)

Oh yeah I know the box thing wasn't very realistic xD and yeah I used it to cut the animation short so was the box the only issue lol?

Aside from box funkiness, you could definitely touch up the motion after the last kick. To me, the drop following it feels forced.