Most complex spelling bias

In English as well as in French, spelling is hard because it doesn't just rely on a definite set of rules. People often make mistakes, switching a letter for another one, sometimes omitting one letters, which has the advantage of simplifying things, and one could perhaps imagine in this case that the search for simplicity was indeed at least partly the reason for making the mistake. For this reason, a simplifying mistake could be more easily excused than a complicating one. (My advice, by the way: if you hesitate equally between two things, pick the simplest one.) But interestingly and unintuitively, incorrect additions of letters or symbols are also very common.

For example, some French people, having seen both the spellings "faites" and "faîtes" somewhere, prefer to write "vous faîtes" ("you guys do") with an accent, which is wrong - "faîtes" being an uncommon word meaning "roof" - over the simpler option, which is correct.
Last month, I even saw an even weirder choice of spelling on a magazine cover. The big title was an injunction to say something: it should have read "Dites..." but it read "Dîtes" with the same accent as above. This time, it really seemed like the author could be given no other excuse for their fantasy than an overflowing imagination. Thinking a little more, however, we realize that this other spelling does also exist. It is the same verb, conjugated with the same person, but using an antique, literary past tense: subjonctif parfait.

In short, when people are unsure about the spelling of a word, given the choice between two possible spellings, it seems they tend to prefer the most complex one. This is what I call the most complex spelling bias.