The right thing to do
Virtuous people do what’s right because it’s the right thing to do. They don’t need a better reason than that.
But nobody’s 100% virtuous. Philosophy and psychological models judge people by simple ideas like virtuousness, but it should be obvious that nobody can be virtuous in all areas of their life, all the time. Learning how to be a positive part of the world takes hard work and serious focus and a long damn time, and it’s an infinite game so you never even get to finish. Everyone is stronger in some areas than others. Everyone has the wrong idea about something. Everyone slips up sometimes.
Maybe the most virtuous person is the one who’s committed to trying really hard.