I could do with a few lightening strikes. Though not lightning strikes! ;-)

If memory serves, the vast majority of lightning is cloud to cloud & it's all bolt. Lightning, quite literally, takes the path of least resistance, so always travels as a bolt. Sheet is simply the reflected flash of a cloud to cloud strike.

I still remember the first time I ever saw a bolt. I was sat in my Instructor's car, waiting to do my driving test (Tanners Lane, Barking). The heavens opened; still one of the heaviest downpours I've ever witnessed. The road gave me a clear view to some tall building in the distance - *CRACK*, oh great that's all I need, test in 10 minutes...

The rain stopped before the test & I passed first time, somewhat to my surprise!