Why is that we don't cherish things or people until they are gone? We only have the mindset to conserve when we are about to run out of it. I suppose it's human nature. When we are confronted, we have a choice - destroy or save. This is where O Sensei's philosophy of satsujinken katsujinken comes into play. We can choose to be the sword that gives life (satsujinken) or the sword that takes it (katsujinken). Aikido teaches us that all life has value and thus must be saved. That is why the techniques are designed the way they are. We could destroy others, but by doing so we would only be destroying ourselves in the process. Life is to be lived, enjoyed and experienced. Don't wait!