I'm fairly certain that everyone has at least one word that they unknowingly and heinously mispronounced for an extended period of time. Mine was adrenaline, which I pronounced "all-der-line". I know, not even close. Since this started in a middle school health class, I was saying it that way for some time before someone finally said something, i.e. made fun of me until I went and looked it up.
Inspired by a comment on the last post, I thought I would share two of my favorite examples of insane mispronunciation. This first link is to a Gawker.TV post talking about a How I Met Your Mother episode in which Ted discovers he's been mispronouncing the word chameleon his entire life. (The clip on the left after the title of the article.)
The second is a trailer for a schlocky Gwenyth Paltrow number called A View From the Top, in which poor, beat down, trailer trash Gwennie changes her life by aspiring to be a first class flight attendant. So you don't have to subject yourselves to the headache inducing lines in the trailer, just skip ahead to about the 1:33 mark where Mike Myers corrects the mispronunciation of Christina Applegate's trainee flight attendant.
I do like to see others stepping in some verbal dog crap. Please share any favorites you might have!