I went out for a decent solo ride on Saturday (what a beautiful day) and came upon a bunch of club riders going along at about 18mph, which was just too slow for my mood. I positioned to overtake thinking 'groan, I know what's going to happen,' then smiled as I went past, saying nothing. Inevitably this was taken as a challenge, and after a while they put on a burst then settled back down to 18mph, so I overtook them again. The pattern then repeated. Although it was quite fun, on the third occasion they just glared at me. If you don't want an extended conversation is there anything you can say that's not perceived as a challenge?