I think I may know what you mean. I can see animation on window-opening it if I hit command-N (new window) in some apps such as Safari or TextEdit, but not in others. I think it's best illustrated by hitting command-N several times in quick succession while in TextEdit. I don't see any animation on closing the windows.
What I am seeing was described in the big Lion review in Ars Technica in July. This section includes the following, under Animation (the reviewer hated it also!):
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Well, guess what happens every time a new window appears on the screen in Lion? No, it's nothing as garish as a water ripple, but there is an animation. Each window starts as a tiny dot centered on the window's eventual position on the screen, then quickly animates to its full size.
You get a window! You get a window! Everybody gets a window!
This animation conveys no new information. It does not tell the user where a window came from, since the animation starts at the final position of the window. Whether or not the animation actually delays the opening of the window, it certainly feels like it does, which is even more important. This type of animation can make Lion feel slower than Snow Leopard. And when an animation like this stutters or skips a few frames due to heavy disk i/o or CPU usage, it makes your whole Mac feel slower, like you're playing a 3D game with an inadequate video card. And for what? For what someone at Apple hopes will be a lasting feeling of delight?
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There is an update at the bottom of that section that gives a Terminal command to disable this feature. This is all one line:
defaults write NSGlobalDomain NSAutomaticWindowAnimationsEnabled -bool NO
I tried it and it works! I had to log out and log back in again for it to take effect. To revert to the default behavior, substitute YES for NO in the above command.