My mother (who learns English as a second language) asked me how to use words like “bored” and “boring”, “annoyed” and “annoying”, etc. Oddly enough, her teacher told her a rule (which is wrong) that “-ed” words are for people and “-ing” words are for things.
Such a rule is a nonsense. The logic is as follows: Adjectives containing -ing or -ed are usually derived from verbs.
The verb “to annoy” means “to make somebody angry”. So, if someone is “annoying”, he or she makes other people angry; if someone is “annoyed”, other people or things make him or her angry. Similarly, the verb “bore” means “to make tired” (in a certain way), so if you say “I am boring”, it means you make other people tired; if you say “I am bored”, other people make you tired.
It works this way for any verb. The reason why my mother was told the rule is probably that for a lot of verbs (such as “to bore”), saying that a thing is “-ed” doesn’t really make sense (it’s hard to make a stone bored, for example). Nevertheless, for many verbs, it does make sense (a stone can be breaking something as well as broken), and the logic is always the same.