had very similiar yest,stopped at lights just outside my house ,(so not really moved /warmed up or anything ,lights went green and i moved off trying to clip in so i was only just rolling ),guy came by me at full tilt between me and the pavement so a pretty tight gap(on a mtb ,and im on a road bike ) he said "cmon you .get going !!!so once i got up to speed i reeled him in easily ,got to the next set of lights ,i stopped ,he caught up ,jumped up the kerb and rode across the ped crossing and carried on the road at the other side of the lights ,now after these lights its a downhill section and i can get a good bit of speed up ,bearing in mind he was away effectivley giving him a head start ,lights changed and im off ,determined to catch him ,caught him up (well seen him anyway )and went down a few gears and determined to pass him did so shortly after ,at what felt like a fair old rate ( for me anyway ,prob about 35 or so ) and he shouted "just cos ur on a road bike " ,,i felt a bit of a smirk and continued at a good pace so he couldnt come back ,
next set of lights i was waiting ,just as they went green and i was moving off he caught up and never overtook ,his words "no point going in front ,after you ,
lol
point proven i think