And on grammar and spelling, spelling is minorly important when compared to grammar. Someone can still get your point if you misspell a word, but the grammar of a sentence can change the subtle meanings contained within and can cause a huge amount of confusion/misunderstanding. Bad grammar can cause someone to miss the point entirely; bad spelling cant (it is annoying at times though).
I wonder why I hear so much about INTPs and precision in spelling, grammar, and math. Im definitely an INTP and only correct minor spelling errors because I hate seeing those red lines under words in spellcheck. Also, I hate math for that very reason: its precision and exactness, I thought that was the reason INTPs don't hang out at IKEA getting all excited about the prospects of better organizing their rooms, I thought we didnt dig things having to be "just so" or there being only one way to do something (like only one spelling for a word).