Probably a boring answer but I know my grandmother’s credit card information. I live with and help take care of her, so she doesn’t mind sharing it with me. Not like I’m planning to do anything nefarious, but I guess technically it could ruin her financially.
That I’ve had to turn down some really cool overseas job opportunities. I couldn’t tell my kids that I even got the job offers because their mother (my ex wife) refuses to consider the move and how we’d need to share the kids time with them overseas.
If I told the kids (now late teens) that their dream of living overseas was stymied so far by their mother’s recalcitrance they might disown her, at least for a while.
It really sucks because not only don’t I get to take the jobs, but I also have to hide my excitement at even getting the offer from my own family so that I can maintain my kids’ relationship with their mother.