Most likely, the company is just afraid of getting tanked by a bug, so they replaced him with someone with more experience. "Every day, I got to build really c

Most likely, the company is just afraid of getting tanked by a bug, so they replaced him with someone with more experience. "Every day, I got to build really cool stuff, all while learning a new language which was unfamiliar to me" Someone who tries to compensate for a lack of skill / experience by working extra hard, like 80 hour weeks, might be a bad fit for a startup and especially for high-risk software like in finance.