So this happened about 6 months ago. It started when I saw somebody I knew and waved at them but they didn't see me and just carried the fuck on walking in a different direction. Unexpectedly, the guy walking ahead of my pal waved back so to save face I just pretended like I knew him.
Now, I don't know why, maybe it's because he responded like he actually knew me, but I suggested we should go for a drink and catch up. This mad bastard actually agreed! So, long story short, we've met up a few times for drinks and, having created an entire backstory about how I have known this guy since childhood, went to nursery and primary school together then lost contact when we started high school I've now introduced him to my mrs. She's now insisting he comes to our wedding.
Tl;DR waved at someone, stranger waved back, accidentally started talking to them, now he's coming to our wedding