One of the first things I learned as an apprentice compositor was that “am” and “pm” are properly typeset “a.m.” and “p.m.” Because I “learned” this by having the error of my ways pointed out to me by my severe (yet goodhearted) mentors, all long-time compositors, it stuck with me. As a result, I am now constitutionally unable to type a time any other way.

Similarly, I cannot misspell beginning because Mr. Sarabura made me write out out 1,000 when I misspelled it on an essay for Grade 9 English.