Early on, before my first test, I began a forward roll by driving my right shoulder straight into the mat and heard a pop. X-rays showed nothing, but I lost three months of training due to severe shoulder pain...I had to shift gears with my LEFT hand while driving. It took me some time to get over fear of ukemi after that, but all is well now and I usually enjoy taking ukemi for others.
I have seen Hapkido demonstrations here in Korea where a practitioner will sprint towards a HMMWV (aka: Humvee, large Jeep) and take a leaping forward roll or even a breakfall OVER it!
You won't see me doing that.