Because I was young and stupid and once I'd accepted the board seat I refused to quit just because I'd go broke. I eventually (after a couple of years) got my expenses back, but not my time or stock losses.
Edit: I haven't thought about this in awhile, so some things popped back, and this part sounds a little emotion-seeking. After I put out a press release about me taking the CEO position and the situation, I got a phone call from what was obviously a very old lady with difficulty speaking. She told me how her broker had encouraged her to invest in the stock, and that it was all she had. I was able to get the SEC to give me a printout (on wide perforated line printer paper, for those that remember that era), and there her name was, with near a million dollars lost. I felt really bad for her, and I had energy and an overprotective nature not yet beaten out of me at that point. Hence the adventure, but with minimal success, other than the jail time for the former CEO. I did get a nice piece of blown glass artwork as a "thank you for the effort" that I quite treasure from an artist famous at the time for making White House Christmas decorations - it sits in my home office.