When you bake something, like a loaf of banana bread, you have to heat up the oven to the target temperature before you put the loaf in the oven. This ensures proper cooking.

Humans generally do not need this. If the house is chilly, one can turn up the heat and put on a sweater or something while waiting for the house to warm up.

OP’s screenshot points out that his girlfriend is expressing the needs of bread. How silly!