Here are some gestures of Japanese people which you should know, so you will understand Japanese people better.
Putting their hands over their chest
Some foreign people mistakes this means "Hello", but not in Japan.
Japanese people put their hands when they pray at shrines or temples,
when they want to thank or apologize in a casual way, and when they have favor to ask.
Before having meal, they do the gesture, meaning thank for meal which God gives them.
Waving their arms up and down means "Come over here",
Do not go away.
Covering their mouths with their hands while you are talking...
They want to hide their mouths while they are laughing.
Japanese people express modesty hiding big laugh.
It does not mean you have a bad breath.
Making a circle with their thumb and index finger does not mean insulting you.
It means "Okey" or "money".
Japanese people rarely rub their thumb and index finger when they mean money.