You shouldn't take money from people that isn't yours.
Sally has a date this weekend that she is anticipating eagerly.
Sally wants to buy a new dress for the date.
Sally spends all the money she had saved and buys the most attractive dress she can afford.
At the store, Sally sneaks some money from an unattended purse and buys a much nicer dress than planned.
The date goes great and Sally is happy.
Sally theft is recorded on the store's security video, and she is later arrested.