apples, jacks and macs

Every time I plug my iPod headphones in my Mac I find myself forcing the plug.
The jack plug won't completely fit in the socket. It fits in my iPod Nano it even fits in my IBM T43 perfectly but I find myself pushing it harder in my Mac because I get the feeling it didn't go all the way in.

User experience and usability are first class citizens in the World of the Apples. These products are all about the way they look and fit in your home and with each other. And still, I have to force the headphones jack every single time. Not only it doesn't go all the way in, but if you push it softly it will stop and then if you push little harder it will go a little more, but not entirely.

I wonder if it's only my headphones plug or my Mac socket. If not, I wonder why in the world an iPod headphones plug will fit anything but its Mac brother.