I have a good workout as a commute and there are a couple of far faster roadies who I presume are doing training runs who fly past me now and then, I have in the past done my best to keep on their back wheels and see if I can pick up any ideas on technique, last time was useful I realised I really wasn’t really using the gears as effectively as I could, others I’ve noticed have very precise body positions for Climbing and chopping along on the flat, many of them seem to be almost glued to the saddle…
Best comeback is to work on technique and fitness then smoke him next summer, no witty comment at the lights or minor act of violence/vandalism will ever make you look or feel any bigger/better than him, as it won’t change the fact that he’s faster on a bike than you…
Maybe ask him for some tips, most people respond well if you are friendly and enthusiastic, you never know he could well help you improve…