[Another original piece of net.humor, from the people who brought you "The Power Users Guide to Power Users" ...]
Note 1: for those who don't already know, an LJBF is a person who, unconsciously and subliminally convinces you that you are without doubt, the man/woman s/he's been looking for all his/her life, then crushes your ego, self-respect, and will-to-live by uttering the four most awful words in the English language:
Note 2: To avoid the awkwardness inherent in non-sexist writing (his/her, s/he, etc.) one has composed this joke from the point of view of a male being LJBF'ed. This is more in keeping with the author's own personal experience :-) No sexist sentiment is intended or implied; female readers may substitute "his" for "her" etc. With that in mind...
Q: How many LJBFs does it take to change a light bulb?
A: Only one, who will...
... call you up every night for three months and talk to you for hours on end, about how bad her current light bulb is, how it goes out without warning, and never provides her with the kind of light she would really love to have.
... tell you what a wonderful light bulb you have, and how any woman would die to have such a light bulb.
... tell you it's amazing that your light bulb has been sitting alone in it's little corrugated cardboard tube for the last six months and even more amazing that you don't have a dozen sockets to screw it into.
... call you up at three o'clock on a Monday morning, (destroying any chance you had of being alert, much less coherent at that crucial business meeting at 8 am) to agonise about the fight she had with her light bulb, and to tell you that she finally lost her temper with it and unscrewed the light bulb forever.
... be shocked at your offer of a replacement bulb, and will tell you that she could never screw your light bulb into her empty socket, that doing so would ruin the light it gives out, and that it's too good a bulb for her anyway, but that she hopes she'll still be able to come over and talk to you about her light bulb problems.
... go home, rummage through the trash can, find the defunct light bulb, lovingly clean it off, screw it back into the socket, and sit there in the dark.
... call you up every night for three months...