lol, you need to tell us really what happened... Some things are just in the games physics.

Best i can think of is if you "slide up smash" people think its a glitch, but its not. Also, some glitches are fine. Like Ikes/Links Final smash on nothing. Others like Shieks chain jacket glitch can cause wii freezing (if you preform it wrong). Some things that arent glitches can also cause game freeze. I know that sometimes, setting off the max amount of smart bombs at once all together can sometimes cause game freeze... Also, if your online and the game freezes its either lag, or a player leaving the match by turning off the wii, not clicking leave or back.