If you don't understand it – don't do it.

Warren Buffett says that he doesn’t get involved in things he doesn’t understand.  Over my career I have violated this maxim, only to regret it.  

It’s not a sin to miss a revenue opportunity.  Trying to take advantage of everything is like trying to eat everything at the buffet.  

Sometimes, you can study a situation so THAT you can understand it before you get involved, but it STILL doesn’t make sense.  Something doesn’t add up.  There are blind spots, parts missing, and bad incentives.  That’s the point. Don’t get involved in businesses or investments you don’t understand.

Good advice.