I often wonder why.  There are a lot of things that take up time but don't lead to anything tangible.  So what's the point?  Travel strikes me as one.  You see new places, take pictures, ahd have fun, but then you're back and it's mostly forgotten.  You resume your daily life just as it was before.  Vacation in general seems a bit overrated as a way of making things better.  You run away from your regular life but when you come back you're faced with the same problems, same worries, and same insecurities as before.  It does help you reset, like a release valve that allows pent up stress to escape.  But it's not a long term solution, for when you return things start to build up again.  Releasing the pressure isn't good because it let's you continue on without ever confronting the underlying problem.

Another why is why try to be friends with someone after you learn that a relationship with them isn't meant to be?  It seems like a reciepe for torturing yourself.  It's an opportunity to be around the person, which gives you pleasure even if it is secret.  It is illusory, though, and that secret prevents it from being a real friendship and probably prevents you from ever being capable of real friendship with that person.  Another alternative is shunning the person, which seems unsatisfactory too.  So you are left in the awakward position of acquaintenceship.

How do you come to the realization that it isn't meant to be?  Sometimes it is just a feeling.  Pessimism and lack of self-confidence skew perception and make it difficult to know whether that feeling reflects reality.  Yet it seems hopeless:  how could it possibly be; it has never worked out before so why should this be any different; is it even an option; if it were an option are there complications that would nix the deal.  Sometimes making the first move is simply not an option due to external constraints.  Those constraints can be convenient to someone already disinclined to make the first move.

A relationship is the one thing in life that I can see a clear answer to the question "why is this desirable."  Going anywhere is better when you're part of a pair.  Someone to talk to at intermission, make conversation with over a meal, be a partner in crime on excursions as varies as trips to the beach or the supermarket (or even a vacation!).  Love isn't just a romantic ideal; it's functional.

Which is not to say there is no place for being alone.  Just not all the time and for all of your life.