Life goes on. You are rid of litigation, you can end the distraction and devote your attentions to getting on with your life or business, you have certainty about the outcome of your dispute, and you have eliminated continuing transaction costs, such as on-going legal bills to handle the dispute.
It is perfectly normal for both sides in a mediation – or most other settlements -- to feel they could have or should have gotten a better deal. This is sometimes called "buyer’s remorse." Experience shows it would be very rare that you truly could have gotten a better deal. Mediation is likely to produce for both sides the best deal that was available at the time.