Anybody else?

If you could take it out and replace it with "it is" or "it has" and it would still sound right, use "it's."

If it doesn't sound right when you do that, use "its."

The apostrophe replaces missing letters - it's not used as a possessive in this case.

See that's the thing, in school I was always taught to use the apostrophe for possessive cases, but apparently that's not correct.

The apostrophe is possessive with nouns (the man's cigar) and proper nouns (i.e. names), but not generally with pronouns (his, her, its, etc).

It wasn't to make you feel dumb.

Thank you, though :)