Also important to note, while 3 years isn't a long time a lot can happen in sports in 3 years. I mean the Thunder's last 5 season win totals are 22, 24, 40, 57, 68. So if you signed with them after the consecutive seasons of 22 and 24 wins, you'd have won a title on that 3 year contract.
So I again say, you should always take the money