or turn the food over, or move it to a different position inside the microwave -- the way microwave works is that it heats up the food unevenly (there's a wave involved).

Yes, my point was that microwaves are advertised as a 'throw your lunch in and get it warm in 1-2 minutes' appliance, but kinda like an LLM, they require some manual effort to do it well (or decently, depending on your standards).

Like:

1- Put it on the edge of the plate, not in the middle

2- Check every X seconds and give it a stir

3- Don't put metal in

4- Don't put sealed things in

5- Adjust time for wetness

6- Probably don't put in dry things? (I believe you needed water for a microwave to really work? Not sure, haven't tried heating a cup of flour or making a caramel in the microwave)

7- Consider that some things heat weirdly, for example bread heats stupid quick and then turns into stone equally as quick once you take it out.

...

I don’t really think repositioning it has a direct effect. An indirect effect of moving it around is that you turn the microwave off for around 30 seconds or more in order to do it. The reason some parts increase in heat faster is that they have higher concentrations of water; allowing the water to stop boiling and all of the heat to spread through is the magic.

(I’ve heard the fans that you hear are there to reflect the micro waves and make them bounce all over the place but I don’t know if that’s true. Regardless, most models have a spinning plate which will constantly reposition the food as it cooks.)

The fan you hear is to keep the microwave generator cool. It's outside the part of the microwave where the microwaves go.

Older microwaves had a fan-like metal stirrer inside the cooking box, that would continuously re-randomize where the waves went. This has been out of fashion for several decades.

> The reason some parts increase in heat faster is that they have higher concentrations of water;

Composition is part of it, but it isn’t the whole story. A microwave oven is a resonant cavity. There are standing electromagnetic waves in there, in several different modes. They have peaks and nulls. That’s why many microwaves have a rotating plate. It physically moves the food relative to the standing waves.