Before there was Clippy and his Office Assistant friends annoying users, before there were so many wizards built to automate tough tasks, there was Bob.  Released to the world in March 1995, Bob was supposed to be a user-friendly replacement to the Program Manager in Windows 3.2.  In fact, several of the "helpers" seen in later Microsoft products came from bob.  Rover, the yellow dog for example can be seen when you search for things under Windows XP.

Bob is generally considered Microsoft's greatest failure, and internally one of it's greatest mistakes.  Microsoft Bob is also usually near the top of the list whenever anyone writes a "Worst Programs of All Time" article.

Fun fact: The Microsoft Bob project was originally managed by Melinda French, who we now know as Melinda Gates.