I think you'd have to believe in something like an omniscient and omnipotent force (e.g. God) to really accept a fully deterministic universe. You'd have to believe that the initial conditions of the universe were just so that all of history would happen to lead to you typing that message, and me responding to it, solely by the physical interactions of particles. It just seems so unlikely to me. It's a bullet I'm not willing to bite. It's actually less ridiculous to me to believe in God determining every action, which I also can't bring myself to do either. All that's left is some form of free will or compatibilism, neither of which are fully satisfying.