This. Let me give an example. When booting a system you can get errors as concurrently booted subsystems (we're talking tens of thousands of them potentially) don't necessarily finish in the order you want, inducing effectively dependency error race conditions. You can either write a totally checked system that is brittle to these race conditions, and many nightmares worth of debugging, testing, and giving up, or you can write floopy logic that accepts the problem, fails, and restarts, and moreover very likely gives you lowered downtime overall. What do you do?