To me chemistry is like a jigsaw puzzle. Each different atom has a number of valence electrons and they come together to form all sorts of compounds based on this, but they can only fit in certain ways, and then you get the chemical equations which balance out and tie everything up. It's all very logical, but it's a different type of logic to maths for example. I think it's cool how elements and compounds exhibit properties; and elements in a certain group or molecules with a certain functional group will have similar properties which differ in a logical fashion. I don't know why I like chemistry really, I just do.
Also, explosions.