It happens to us all the time: one little slip on the keyboard, and a "protector" becomes a "protestor."
Typographical errors are not fun for the committer, perhaps, but they can be highly entertaining for the rest of us.
Scottish editor and author Drummond Moir proved the point with his book of some truly classical typing gaffes, called Just My Typo.He visited the Exchange for a rundown of some notable examples in 2014; we hear that interview again here.