Looking through here I see SOOO much information on different excersises and best excersises and whatnot I have no clue what to do! I see tons and tons and tons of ab excersises. What are the bets ones? I'm sure it opinionated ane everyone has variation, but are there any like 2 that most here can agree are the best, and then the disagreement comes with wanted another 2 to supplement? What does everyone here think are the most effective?