Because a Lannister always pays his debts.
Stop paying the bill.
Shopping never causes heart attacks, but paying the bill does!
When he was told to "go big or go home," he only had one option. (I've posted this joke here before, but I believe I've been the first, so if you recognize it as a repost it's because I wanted to tell it again!)
Because dogs can't whistle. (X-post from r/dadjokes)
They pushed two twins together and made a king.
Because it's Greek.