system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why/how does it matter if your oven is warm or not before placing your Pizza or other foods inside? Does food end up different if you wait until the oven is fully warm first?
gpt
Mostly it's to standardize the baking time.  One oven may heat from 70-350 in 5 minutes, another might take 10 minutes, it might be 90 degrees in your kitchen one day and 65 another so it takes a different amount of time to heat.

So if a pizza takes 10 minutes to bake at 400, and you put it in without preheating, after 10 minutes it probably won't be done.  And it might take another 2 minutes or another 15 depending on how slowly the oven preheated.

With cakes and bread this is especially important because opening the oven to check if it's done will blast it with cooler air and it will sink and flatten out if it isn't cooked enough to stay fluffy.