In Japanese society, bowing is an extremely commonplace activity. The bowing process has its own set or rules and procedures and these can get somewhat complex.
Bowing is used to express politeness, respect and humility, all at the same time. It can range from bowing in a somewhat automatic manner to a customer in a store or it can range up to the extreme form of getting down on the floor, the person's forehead against the ground in an all-out bowing action.
From the book The Japanese Self in Cultural Logic, 2004:
"In bowing, angles of the upper body to the floor signify the levels of politeness, ranging from deepest obeisance to a light nod, each level of which has a name. One extraordinary gesture of awe is called ‘dogeza', in which one kneels with the entire upper body lying flat on the ground-the Japanese version of prostration."
The general principle is that the depth and length of the bow depends on the status difference (real or perceived) between the two people. In other words, if the person you are bowing to is of a higher status then you are, your bow will be deeper and longer held than theirs.
The methods are different for men and women, and is easily seen whenever one watches any Japanese doramas, for example. I've even watched TV shows featuring, for example, Morning Musume on a talk show and the girls all bow when they are introduced. It's basically a form of politeness and respect that's takes little time, costs nothing and can help social things to flow more smoothly. Nothing bad about that at all, really.
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