The Cupboard fascination

Since moveing to my new apartment the cats have been obsessed with the kitchen cupboards and the batroom medicine cabinet. I have to put a chair in front of them when I leave for work every day or else the cat is in and everything I own is out. I need to install child locks but I need to know what is it about any closed door that drives cats batty?
Does everyone's cats do this or is it just me?

out of the 2 cats and 1 kitten we have here the only one that is obessed with cabniets is our 5 yr old all black cat Azzie. he will sit in front of a cabniet if he can't get into it crying til we let him in. we have one in the kitchen that is completly empty and it is just for him, we found that easier than always having to deal with the mess that he would make to get into one(he weighs about 20 lbs). he will occasionally bring one of his furry mice in there with him after he has "killed" it. what we did is put the child locks on all the other cabniets and he learned that he had his own "space" that he could go into to avoid my kitten who follows him around in a hero worship way. now he goes in there to get away from the new babies.

The cabinet under the sink is "Plasticbagland" and Zissou has been exiled from it...obviously. There's no way to childproof these cabinets, but we fasten the two handles together with a bug thick rubber band. She tugs at it trying to get in several times a day but never can. She doesn't seem too interested in the other cabinets, though.
She also loves the med cabinet in the bathroom, cause that's where I keep all the shiny stuff, necklaces earrings etc. That stays closed else I find my various girly stuff (mascara, earrings, etc) in either the litterbox or on the floor.

Cats never like not being allowed in somewhere in my experience!

I think it's because they figure if you aren't allowing them into it, there must be something really cool in there and they want to get at it.

One of our cats likes to walk up to the cupboard door and open/shut it repeatedly. All we hear is SLAM! SLAM! SLAM! SLAM! It is SOOOOO annoying when she does it! We had to put child locks on ours too.