Every time I get lonely I want to adopt a puppy. Then I struggle with the thought of my incapability to make him happy because of my lifestyle (I don't have my own house and move frequently)... Of course I feel even more miserable than before when my sadness was caused by my loneliness.
Why not go to the local pound and taking the dogs on a walk? That way you can feel the satisfaction of providing happiness to less-fortunate animals and not have to worry about owning one.
This happens at least once a month.