Anyone who types for a worthwhile amount of time recognizes the typo and the braino. The introduction of the keyboard made dumb errors more possible, but I’m certain that Shakespeare scribbled a spelling error now and then (given how vowels traveled and disappeared in written English back then, they properly had “yee olde” courtesy not to point it out and just assimilated them as alternate spellings).
Today, a typo is "tp" instead of "to." A braino is "too" instead of "to." You know the difference between these words. You know when to use them. Sometimes your brain fumbles, just like your fingers do. There's no reason to be embarrassed about it. Sometimes I've braino'd entire sentences out of existence, giving me the paragraph-sized embarrassment you get out of writing “too” instead of “two.”
I spell these things “typo’d” and “braino’d” with apostrophes instead of traditional pluralization as a tribute to the nature of the typo and braino. Like the little toe and being unable to sneeze and urinate at the same time, these are the human experience’s ways of telling us to stay humble.