Long ago, like 5 years, I made an app for my EX GF in symbion to track her periods. Application predict the next date when your period will come based on her cycle.

How ever after 2 month of usage she told me that application was flashing that she is pregnant. She scared shit out of herself and made me sacred a hell as well.

Later i find out that the variable i used to store number of days between last period and current date was not capable of storing value more than 40, i don't know how, and triggers negative value to be shown.

Early days of my programming, Shit happens.