I had a sheltie. I was a big fan of Lassie when I was younger, and when my aunt and uncle got a sheltie, I knew that was the kind of dog I wanted.
I got her around my 9th birthday, and she lived for 12 years. When she was gone, that was the toughest loss I've ever suffered. Today, I feel like a dog would help me cope so much with my loneliness, but to me, getting another dog seems on par with remarrying after your spouse has died. I'd feel guilty, like I was replacing someone who couldn't be replaced. I know I'll get another dog someday, but 5 years after her death, the right time still hasn't come. I also feel like, with me living alone, it would hardly be right to raise a puppy while I'm gone to work all day.
All the time, I hear my boss (who I suspect is AS, actually) say, "Dogs are in every way almost always superior to humans."