CNET has two top 10 lists of the Best and Worst products of the past 10 years. Here's the #1 from the worst list:

I want to say that it was a good idea in the beginning. Bob was born out of Microsoft's goal to improve the Program Manager interface for Windows 3.1. But it was a replacement that just didn't catch on. It also suffered the ignominy of spawning the awful Clippy--the helpful paper clip. Maybe Bob wasn't universally bad, but I've never heard anyone say they miss it. On a side note, according to Wikipedia, "Microsoft Bob was a project managed by Melinda French, Bill Gates's girlfriend at the time. The two later married. Bob was the last project she ever worked on for Microsoft

This news article was written on September 20, 2005, quoting CNET News.