Some of your friends who are committed to pessimism may question or judge your new attitude. Some may find fault with it. But some will be intrigued and drawn to it and to you. And you may also find that there are other "closet optimists" who welcome your perspective into their world. What have you got to lose by trying?
Your outlook is a product of your own relationship with expectation. What will or won't happen, no one knows. And how we deal with the stress of not knowing, whether to hope for the best or expect the worst, the idea that our expectations always directly affect an outcome is little more than magical thinking.