If you want to see crazy sheep try working Cheviots or Barbados.
We have worked both, and crosses of both with other breeds. Never really had any problems except for a few Barbs that tried to fly. The facility where we train has a Kathadin flock that varies from year-to-year...this year's was not very good, and at the end of the spring trial season saw a lot of them going to market!
I have a good friend with a small flock of Barb/Dorper crosses that are pretty nice to work.
The sheep that have caused me the most pain were a set of St Croix...big idiots.
