I read my parents bank statement when they went out for the evening.
What was your reason for reading their bank statement anyway?
I wanted to see what they're spending their money on.
Reading your parent's bank statement is wrong because that is their private financial information. It's none of your business what they spend their money on and you should not look into their financial affairs.
It was just random number jumbles that were relevant to me.
It is an invasion of your parents privacy to go and read through their banking statement. This is their mail to go through, and trying to see everything that they spent money on is not your business.