We can no longer pick just "the most important thing"; RATHER making any field of human activity, in which you ARE personally much involved, empirically better will help not only that field but tend to help the modus operandi in several/many other fields. Any major change will be inspirational -- and some of this will be useful and in appropriate ways more generally useful. (This may seem self-serving (on my part), but I really believe "you do what you can, where you can" is part of an individual being her/his best and THAT MATTERS more generally. Otherwise you just have some small positive effect on the "most important" matters. Obviously, you do what you can there; but, given your actual expertise, this effect will be limited. )