It's an interesting phenomenon that when you cycle with someone you go faster and further. I first noticed this last year when I bumped into A, who follows the same route as me. He's a serious bike-porn reading cyclist and tends to go super quickly.
He dutifully slowed down and we went in together. I said he could overtake and I wouldn't be offended but he generously mentioned it was nice to go at a sedate pace for once. We got to work and as soon as he'd gone round the corner I sat on the floor as my legs went to jelly and tried desperately not to throw up.
I'd cut 10 minutes off my usual time.
On the midnight ride I attempted and conquered hills I'd never have usually gone for because I was in a group. The combination of pride and distraction while you chat means you fail to notice it hurts or that you're exhausted.
I bumped into A again this morning and in we went. It's been a while since the last time and I'm noticably quicker now. It makes the journey go much quicker and is way more fun so from now on I'm going to target strangers and, unbeknownst to them, attempt to be their pace buddy.
If you see a blonde cycle stalking you it may well be me so try not to go too quickly!