"What the hell just happened"

[vincent]

My wife and I just spent the weekend riding in the North Carolina mountains. It was beautiful. On Friday afternoon I pulled off the main road headed up the hill into our motel parking lot. I came to what felt like a controlled stop on the hill in front of the office and a second later plop the nad was on it's left side. When my wife climbed off she looked at me and said "what the hell just happened." I wish I knew. I have seen this topic before and any experiences, advice or help would be appreciated. I'm trying to avoid a repeat performance. (no damage or injury)