How to Build a Red or Yellow Deck?

When you rest, you get the opportunity to forget one of two cards. Cards have like a level to them, so it looks at your worst cards and tries to pick ne of those. One in five times it won't, and it'll just give you a good card instead. It's something like that. Because every now and then i got like two pretty good cards. And like, you having not forgetting any of these. I've been having a devil of a time getting the cards i want to forget in th game.