Linux failed to keep me happy, even after I moved from Ubuntu to Arch, then to Gentoo. I now live comfortably on another little-known OS, one with forward-thinking ideas.
Linux cannot provide the security guarantees I need to feel safe. I wanted an entirely new approach. Such a system does not yet exist in a stable state, but I did find an alternative that solves my problems, and it doesn't even require that I give up Linux.