It's bad to steal someone's wifi.
Jason is out on the street and needs to access his email with his phone, so he goes into settings to connect to the internet.
Jason wants to choose which method to connect to the internet with.
Jason goes into data and turns it on and uses the mobile phone network to connect to the internet.
Jason goes into wi-fi and finds an unsecured connection which he uses to connect to the internet.
Jason is able to access his email without problem and get what he needs from it.
Jason is caught by the owner of the network and booted out before he can access his email.