I agree with those who say the question needs rephrasing. A ride on the most "boring" motorcycle in the world would still rank above most other activities I could choose to do.
That said, the bmw F800 ST was a major disappointment for me. Highly functional, a great commuter, so efficient at getting from point A to point B. But riding it, I always felt like I just couldn't buy a thrill. And for all the visceral stimulation I got from the engine, I might as well have stayed in my kitchen running the blender.