My most consistent error is reversing characters - mostly "er/re" combinations and occasionally substituting a "t" for a "y" - and vice versa. The previous sentence could have started out: "My mosy consistent error is revresing charactres..." (this one
actually started out "The pervious sentence..."). The reversal also happens with "mn" and "we" - as in "condenm" or "oil ewll". I will also sometimes double the wrong letter (as in "finaaly" for "finally").
The strangest typo affliction I had for a while was inserting a rogue "r" into words that ended "-tion". I think I've prett much broken myself of the habit, but I still occasionally come up with a "conceptiorn" or "productiorn". I have
no explanation for that one.
Thank God for Spell Check - I just wish it replaced all those {curly brackets} with [straight ones].