I don't have an extremely embarassing story, but a couple that made my want to walk away forever.
At Cafe Orleans at Disneyland, the line was really s l o w, so I decided to speed some things up by grabbing my Chocolate Milk ahead of time. The chocolate milk was buried in ice water, and I reached across another gentleman's clam chowder, and about a quater cup of water came splooshing into his meal. I felt so bad! He just laughed and said that he had kids. The cast member that was right there (she was serving the desserts) gave him another clam chowder bowl.
A couple other times I was embarassed was when this one cast member photographer was taking pictures by the Paradise Pier entrance. Just in the middle of what was probably a perfect shot I just walked right into. The cast member was understanding and gave me the picture ticket instead of the group.

I also once lost my wallet in DCA and told just about every cast member I met that I had lost it. After about an hour searching at about 40 cast member later I discovered that my wallet was in my back pocket (I rarely put anything there). I just ran across to Disneyland I was so afraid that I'd meet a cast member that I had talked to again!