honest and white lies

honesty is a kind of virtue that we all should have. but sometimes, we can make some white lies. maybe that will be more suitable for some special situations. for instance, when you face a patient who has no idea he got such serious ill, it will be better to tell a kind lie to him. for another example, on the April 1st, won't it be very funny if you make a little joke to your friends?
of course, we should become a honest person. however, everything depends on the situation.right?