Because while one can respect and even like oneself, one cannot be devoted to oneself or merge with oneself
The desire to merge with a beautiful soul and give it everything it needs is what invigorates. The transcendent energises more than the ego ever can
Why can't people be that way for themselves when alone?
This has been troubling recently.
When a potential love interest appears — even just the possibility — there is suddenly an extra spring in the step, more drive and a stronger desire to get things done