From an interview with Vincent Connare, creator of Comic Sans:
Q. What do you think of comic sans’ detractors?
A. I think most of them secretly like Comic Sans — or at least wish they had made it. Interesting fact: the main designer at Twitter tweeted that the most server space is used by complaints about: first, airlines; second, Comic Sans; and third, Justin Bieber. So not even The Bieber can beat Comic Sans!
Here’s the tweet he’s talking about (it’s from 2010.) Also:
Regular people who are not typographers or graphic designers choose Comic Sans because they like it, it’s as simple as that. Comic Sans isn’t complicated, it isn’t sophisticated, it isn’t the same old text typeface like in a newspaper. It’s just fun — and that ‘s why people like it.
“It’s like, ‘Not only am I going to refuse to submit these documents, but I’m going to use a typeface that doesn’t submit to the solemnity of the law, and Congress and public institutions,” said Michael Bierut, a partner at the design firm Pentagram. “Or maybe he just likes Comic Sans. It’s hard to say. Few typefaces are this freighted with public opinion.”
I think these are the final words on the matter from the creator himself:
If you love Comic Sans you don’t know much about typography. And if you hate Comic Sans you need a new hobby.