I once bought a system that was based on the Asian market. Worked great for 2 years, then one day - boooom
I think a lot of traders here would give anything for a system that works for 2 years. Most of them have the 'boooom' on their account far earlier..
That's why I won't sell anything. I know my risk, and my investors also do. That's why I trade only the manual way, never ever automated stuff (because a robot never knows the market (e.g. Trump's tweets)).
I made most of my money during/after flashcrashes. Nothing more to say here. 😉