This user believes that only left-handed users are in their right minds.
its & it's
This user thinks ohh, if you want it to be possessive, it's just i-t-s, but if it's supposed to be a contraction, then it's i-t-apostrophe-s... Scalawag.
Obsessive spell-checker. Misplaced apostrophes drive me mad. On rare, painful occasions, the Californian English totally rears its awesome head. Still having trouble with markup (how do I put the paragraph under the boxen? Why does correctly linking the structural ruin my table, but removing it completely doesn't fix anything?), and trying not to treat this as a private sandbox too much.