That's the fundamental difference, isn't it? Kate knows life is temporary, knows her life is temporary, and wouldn't have it any other way. The thought of filling out endless amounts of time, watching people come and go through centuries?

If she were Red Wine, she'd have already gone mad.

But at least... "Got your answer, then." If he thinks it isn't worth it, and doesn't like being alone, the answer is simply to keep making friends, isn't it?