The titles "Mr." and "Mrs." are so commonly used in everyday interactions that no one really thinks twice about them.

Obviously, "Mr." stands for "Mister" and "Mrs." for "Missus." But, doesn't "Missus" sound so awkward written down in full? 

It turns out that everyone used to think so as well. I feel like if anyone were to write that to me, I would assume they would want me to read it in a bad Southern accent.

https://www.youtube.com/embed/PoUC22qR3Lk

The crazy reason why the word 'Mrs.' has an 'R' in it

According to Mental Floss, the original meaning of "Mrs." was Mistress.

But it's not what you think, though wouldn't it be a weird contradiction that the abbreviation of your married name is a word commonly used for the other woman? If you're an avid reader of the classics (i.e. Shakespeare, Dickens, the Brontë sisters), you know that the definition doesn't have the same meaning it does now, in fact, it meant the exact opposite.

Although, both of those words existed at the same time. Hah! For once, I have an advantage over people who used to make fun of me for reading Jane Austen novels.

The Mistress wasn't "the other woman" of a cheating husband or a sexy dominatrix (there are two kinds of people in this world, even back then); she was the female head of a household or a governess who looked after the children.

It was also a title given to married women who were often called the mistress of their household. In short, it was the female version of "Master." Typically saved for the nobility. 

Sometimes I just want to dress up in a ball gown I just have lying around and talk in a really bad British accent and make my friends and family call me mistress, as I pen a letter to my long-lost lover who my father won't let me marry.

Speaking of which, back then, "Mr." was used for "Master" but was changed later on to "Mister" (the word did exist to mean an occupation or a skill). 

Mental Floss said, "Eventually, the title form took on a contracted, 'r'-less pronunciation, and by the end of the 18th century 'missus' was the most acceptable way to say it."

Mystery solved. Now go use this fact to woo and find your own mister, or at least entertain at your next dinner party as you try to forget the lack of Mrs. in front of your own name. Now you don't even have to be married to run your own household.