What is the worst case scenario if the engine light is on?

What is the worst case scenario if the engine light is on?
You have no oil pressure and are doing permanent damage to the engine internals which will result in overheating and the engine will stop running, maybe seize maybe break, might even catch fire.
If the check engine light flashes while your driving and you continue to drive it, you will probably cause serious damage to the catalytic converter which will cost $$$ to replace.