system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it important to let an engine warm up in winter?

What could happen if someone doesn't let an engine warm up?
gpt
Back when engines used carburetors, cold engines would need to be warmed in order to get the proper fuel-air mixture for sustained ignition/combustion.

Nowadays, however, it's entirely unnecessary; engines have fuel injectors and sensitive instrumentation that adjusts the mixture for optimal combustion.