DEAR HARRIETTE: I have a young woman in my life who is important to me. I consider myself her mentor. She calls whenever she needs anything, and I do my best to be available at a moment’s notice. I am beginning to see, though, that when I need her, she is often MIA. If I text or call her, I may have to follow up three or four times before she responds. Meanwhile, if she texts or calls me, I do my …