Скачать или смотреть 『GENKI 2』Lesson 21 (1)┃THE JAPANESE PASSIVE VOICE・PASSIVE SENTENCES

When you are inconvenienced by something somebody else has done, you can express dissatisfaction using a passive sentence.
In Japanese, the passive voice also is used when the speaker wants to inject the sentence with emotion.  For example, Japanese speakers often use the passive voice in situations where they want to convey a sense that they are a “victim”.  In other words, they use the passive voice to describe when something bad has happened to them.
One reason is that both the Japanese language and Japanese culture are very indirect – as a result, the passive voice is more frequently used in Japan than in some other countries. 

In the passive voice, it is the subject that is acted upon by somebody else; while in the active voice, it is the subject that is doing the act.