Go to networking settingsI trust you have now changed your password having displayed it to one and all on youtube!
You can also use wirelesskeyview:
WirelessKeyView: Recover lost WEP/WPA key/password stored by Wireless Zero Configuration service
I wonder if it's possible to find neighbors' wifi password in some way haha
sure! It was more of a joke.Yes it is possible depending upon the type of ciphering and standards and some features make it easier but it is not legal and we won't share that kind of information nor should you try and break into a network you don't own or have the express permission of the owner.
Become their friend and you will know even what they have inside their house
It is called "insider attack".