Answer: Comic Sans
Comic Sans is by far one of the most malignant and disliked fonts in the world, and not entirely without reason. Designed in 1994 by Microsoft designer Vincent Connare, it was originally intended to be part of Microsoft Bob for use in the comic style bubbles of the application. The project was completed too late for integration with Microsoft Bob and Comic Sans ended up in Microsoft 3D Movie Maker.
The writing type was later included in Windows 95 Plus! Pack and eventually rolled into standard Windows 95 editions. Eventually Comic Sans came as one of the standard fonts for Microsoft Publisher and Internet Explorer. It was here that Comic Sans went from a cute but rarely used font suitable for children and comic books to a font used by hundreds of thousands of people just because it was one of the standard fonts in Microsoft Publisher.
As a result of that view, Comic Sans pops up everywhere (often improperly). Whole sites are devoted to explaining why Comic Sans is a bad choice ̵1; like Comic Sans Criminal while others catalog bad uses for the font. In short, only the font is used quite often in places where a rounded comic book is a bad choice and very rarely in real contexts where the sign would be meaningful (as an elementary school leader).
What should the designer Vincent Connare say about it?
Comic Sans was NOT designed as a font but as a solution to a problem with the often overlooked part of a computer program's interface, the font used to communicate the message.
There was no intention of including the font in applications other than those intended for children when designing Comic Sans. The inspiration came at the shock of seeing Times New Roman being used in an inappropriate way.
For a much longer treatment of the subject, you can visit his personal website.