The only times I have ever got stuck, bar once, is as said above, diffs hit the floor and pick up wheels. (the once was a situation involving deep mud, and i got opposite wheels dropped into little dips with big muddy rocky bits they couldn't pull up)

I saw a LR on ebay once that had a 10 inch lift... I kid you not! Looked really stupid too cos it was about as tall as it was long.