I don't regret, and I did leave the big tech after a few years to build another company with some of my colleagues that I met. Since I started the company quite early in my career (about 12 months out of college), I think building the company gave me focus in my early 20s which would have otherwise spent with video games / internet / counter productive things. The added advantage was that I committed fairly costly mistakes but the cost was discounted since they occurred pretty early on in life. I do have slight regrets around how I treated some of my co-workers, including people who were more powerful than me, and I think being a founder early on without the right level of maturity was rather depressing, so yes, I would start a company after a year of employment and some built up savings but do it with more maturity and self awareness.