Show HN: Quantifying opportunity cost with a deliberately "simple" web app

Hi HN, A while ago I had a mildly depressing realization. Back in 2010, I had around $60k. Like a "responsible" person, I used it as a down payment on an apartment. Recently, out of curiosity, I calculated what would have happened if I had instead put that money into NVIDIA stock. I should probably add some context. For over 10 years I've worked as a developer on trading platforms and financial infrastructure. I've personally never traded on public markets. Early on I made a simple rule for myself: "never play". In 2015, when Bitcoin traded about 300 usd, my brother and I were talking about whether it was a bubble. He made a bold claim that one day it might reach $100k per coin. I remember thinking it sounded unrealistic - and even if it wasn't, I wasn't going to break my rule. That internal tension - building systems around markets while deliberately staying out of them is probably what made the "what if?" question harder to ignore years later. The result was uncomfortable. The opport