ELI5 Microwaves - why can't you put metal in them?

Why does microwaving a mug of water alongside a frozen bread roll, keeps the bread from getting soggy? Why can't we put metal objects in the microwave? Especially since the inside is made of metal, including the metal mesh on the inside of the door! How does a meal that takes 30 minutes to cook in an oven cook in 4 in a microwave? There are so many questions about microwaves!   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community as always and in particular the following users whose questions and comments formed the basis of this discussion: florinator, wbeaty, high_onthemountain, metricprime, yeahsurethingbud, thewyzzerd, chairmanzuck, soulwager & celtickdk. To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]