The answer is almost certainly "it depends".

And it depends on stuff you won't be able to discover.

What do you mean by "ceramic"? Anyway, its the enamel that worries me.

Some ceramic items shouldn't go into the microwave because they have metal embellishments or trim. Some ceramics have lead glaze, which means they're not food safe once cracked or chipped, but I can't say whether microwaving them would make them more dangerous or less food safe.

> > For most Americans, they don't have glass plates/bowls at their work

As a note, most people I've seen microwaving their leftovers at work were microwaving plastic because that's how they packaged the leftovers from home. If there aren't dishes at work, let alone a full kitchen, then leftovers are transported, heated, and eaten from the same container.

Some ceramic bowls turn into lava in the microwave. Often when I reheat soup in a bowl, the bowl becomes hotter than the soup. The bowl is too hot to touch, yet the soup is only somewhat warm.

Some bowls are more prone to this than others, but it's not obvious and requires experimentation to determine. It's a pain.