True story (sad): A few weeks ago I was approached to do a database program. I heard the basic proposal, and said that it didn't sound too bad. Today I attend my first meeting for the project (a warning sign right there) and my rough estimate is that the project is about three entire orders of magnitude more difficult than I envisioned from the first pitch. *sigh*
True story (funny): I added parsing and opening external HTTP URLs to the personal wiki project, and there was a bug in the regex I used to parse URLs. This bug mangled the URL in just the right way that when I entered a test URL and clicked the link, it brought me to a porn site.
Just imagine that on a bug list: "BUG: program pornifies links to external websites."