From Alexander the Platonist I learned not to tell people "I'm too busy" unless it's really necessary. And not to keep putting off what we owe our friends and family by claiming we have urgent business.
Of Alexander the Platonic, not often nor without great necessity to say, or to write to any man in a letter, 'I am not at leisure'; nor in this manner still to put off those duties, which we owe to our friends and acquaintances (to every one in his kind) under pretence of urgent affairs.