When I was 11, my parents got me a ZX81 kit - so it came as a motherboard and components. I eventually
* soldered it all together, worked through the (excellent) manual, and marched into the family living room to link it up with the TV there.
I typed the example in the manual: PRINT 2+2=4
To which the computer responded: 1
And my dad, not exactly au-fait with boolean logic, looked at me, and said with disgust "I knew it, you've buggered it". It took weeks for him to finally believe that the machine was working perfectly.
Anyway, that set me off down a path that literally changed my life. I next got a TI99/4A on the strength of watching Parsec, then realised the built-in basic was, well it was terrible is what it was. Up came Xmas and I managed to sell the TI99/4A to some poor unsuspecting sod (on the basis of showing him Parsec), and fund the purchase of an Atari 800XL - Dixons were bundling it with a .... disk drive for £99. A disk-drive was *fast* (well, fast*er*) and could store 127kB of data on each disk... How could anything be better than that ?
Much fun was had, and I upgraded to an ST when I left for college - that machine with its mono monitor, awesome printer drivers, and a few creative programs made my lab reports stand out so much I'm pretty sure they're responsible for my degree result being a grade higher than I'd expected.
Did a PhD in physics, eventually left to join an internet startup (when you had to email CERN to let them know there was a new website in the world), launched my own company; went bust. Launched another; got bought by Apple. Spent a couple of decades living the dream, and retired.
So yeah, I sometimes wonder what might have happened if my parents hadn't bought me that computer...
*: I'd put off actually building the computer. They also got me a black-and-white 12" portable (with a dial-tuner) and I had my own TV in my bedroom. I even used to watch snooker on that thing

Eventually my dad called me on not putting together what he thought of as "the real present" and ... well you read it above...