It's no exaggeration to say the ZX81 shaped my entire life!
I first saw one when I was babysitting for a friend and they'd just got one. I was immediately captivated by what was the first computer I'd ever used "hands on" and saved all my money to get one of my own.
I taught myself Z80 machine code but as I couldn't afford an assembler program, I hand translated the assembler into machine code and sold a game to DK'Tronics for £200 and a ZX Spectrum (which seemed like all the money in the world to a 16 year old me)
Since that moment, my entire life has revolved around computers and software development and even now (37 years later) that's how I put a roof over my head and food on my table
For me, the ZX81 launch was quite possibly the most important event in my life and one for which I'll be forever grateful