A while back, a local shop showed me a burnt out wreck of an almost new Greenfield that someone had flipped by giving it too much stick going up a steep bit. The operator jumped off the back, but the mower went over and spilled fuel that caused it to catch on fire. The amazing thing was he wanted a quote to repair it. It looked like a write off to me, although I have no doubt a few people on this forum could resurrect it.
I have a few steeper bits on my property and have had to jam a leg down in the past to keep all 4 wheels down. I now know the tricky bits and don't have problems. Be careful.