I don't care if you can't spell—try your best and we'll figure it out—but these mistakes make me cringe.

• writing plurals with -'s, as in "All shirt's are on sale."
  • How did this become so pervasive? Argggghhh.
• confusing "your" and "you're"
  • It's really not that hard. Just think about it.
• confusing "their," "there," and "they're"
  • Same as above.
• confusing "are" and "our"
  • I don't even know what to say about this one...
• adding "of" at the end of verbs, as in "should of"
  • It's "should've," as in "should have"!