pardon me while i burst
sorry about the Incubus ref, but it is totally appropriate for the following public service announcement:
"We now know that every particle has an antiparticle, with which it can annihilate...There could be whole antiworlds and antipeople made out of antiparticles. However, if you meet your antiself, don't shake hands! You would both vanish in a great flash of light."
--from the chapter "Elementary Particles and the Forces of Nature" in A Brief History of Time by Stephen Hawking.
i know if i hadn't read this, i would probably have shook hands with my antiself. so i thought i'd pass the info on.