Nothing, unfortunately, simply because my PayPal funds will be available two days after the sale is over. It always happens anyway, since we never know in advance that there will be specific deals I can never make sure to have funds for that specifically, so I bought other things (components) and games at GoG which happened to be exactly two days before the sale occurred, when I saw the sale I immediately sent new funds to my PayPal but due to the holidays work schedules it won't be ready until January 5th.
Had I been able to buy something I would have bought three games, at least. There's one positive thing in all that however, I just have more time for myself instead, and there's always deals on Steam, I just never know when. I don't know much about business, but if they announced that "special sales" and "deals" would happen about one or two weeks in advance without necessarily telling exactly what will be on sale then at least consumers could prepare their finances accordingly "just in case", alas I think that Valve themselves don't know about such details of sales for the games that do not concern their own business (by that I am referring to the games that they themselves published or developed).