I think one should forgive and remember .... If you forgive and forget in the usual sense, you're just driving what you remember into the subconscious; it stays there and festers. But to look, even regularly, upon what you remember and know you've forgiven is achievement.
Core strength and stability is very important to me. Tennis is all about rotation of the body and my ability to create power. I incorporate a lot of abdominal back and glute exercises into my gym sessions.