Yeah, but even with integration & unit tests, people regularly miss some corner case. Again, maybe I just don't know enough about how it works, or maybe I just

Yeah, but even with integration & unit tests, people regularly miss some corner case. Again, maybe I just don't know enough about how it works, or maybe I just know enough about what I do -- but every once in a while you make some catastrophic mistake that takes done Google or Facebook for a few minutes -- the only cost you incur is opportunity. The same mistake at Knight Capital cost them like $500M in 15 minutes or something crazy. So, taken a step further, the little bugs that regularly make it into Google that cause 1% of requests to 500 on some service is a big deal, the opportunity cost can exceed your salary for years. I imagine the same thing is true in trading, except it's not opportunity -- it's real money. That just seems way more stressful to me, but maybe it just doesn't happen very often, or the test coverage is taken much more seriously, and it's better.