""Kissing a wonderful way to express your feelings. It is a sign of affection. ""
Absolutely! I agree.
Its a communication medium.
Something is communicated during that moment.
Similarly to the way a pat on the back communicates something.
The poster that feels it is only to lead to sex probably doesn't experience any depth of intimacy.
Thats kind of the way it is in the animal world.
My brother use to breed horses and I would be around occasionally during "the event."
There is no intimacy involved.
There's different rituals that they go through, similar to the way the kissing was described in order to get to "the event."
To the original poster, it may not have happened yet due to not finding yourself in a position for it to happen.
I suggest signing up on some kind of dating service and you will likely find yourself in that position someday.
Sometimes in life things don't fall in our laps until we put some momentum towards what we want.
Once you find yourself there, the mystery about it will be behind you.
Its really not a big deal, but wondering about it creates a mystery and that mystery can make it seam like a big deal.