To speed up execute following command:

defaults write -g NSWindowResizeTime -float 0.003

Quit and relaunch all apps for the change to take effect, including Finder

To undo:

defaults delete -g NSWindowResizeTime

Some others:

# opening and closing windows and popovers
defaults write -g NSAutomaticWindowAnimationsEnabled -bool false

# smooth scrolling
defaults write -g NSScrollAnimationEnabled -bool false

# showing and hiding sheets, resizing preference windows, zooming windows
# float 0 doesn't work
defaults write -g NSWindowResizeTime -float 0.001

# opening and closing Quick Look windows
defaults write -g QLPanelAnimationDuration -float 0

# rubberband scrolling (doesn't affect web views)
defaults write -g NSScrollViewRubberbanding -bool false

# resizing windows before and after showing the version browser
# also disabled by NSWindowResizeTime -float 0.001
defaults write -g NSDocumentRevisionsWindowTransformAnimation -bool false

# showing a toolbar or menu bar in full screen
defaults write -g NSToolbarFullScreenAnimationDuration -float 0

# scrolling column views
defaults write -g NSBrowserColumnAnimationSpeedMultiplier -float 0

# showing the Dock
defaults write com.apple.dock autohide-time-modifier -float 0
defaults write com.apple.dock autohide-delay -float 0

# showing and hiding Mission Control, command+numbers
defaults write com.apple.dock expose-animation-duration -float 0

# showing and hiding Launchpad
defaults write com.apple.dock springboard-show-duration -float 0
defaults write com.apple.dock springboard-hide-duration -float 0

# changing pages in Launchpad
defaults write com.apple.dock springboard-page-duration -float 0

# at least AnimateInfoPanes
defaults write com.apple.finder DisableAllAnimations -bool true

# sending messages and opening windows for replies
defaults write com.apple.Mail DisableSendAnimations -bool true
defaults write com.apple.Mail DisableReplyAnimations -bool true


Again to undo:

defaults write -g NSAutomaticWindowAnimationsEnabled -bool false
defaults write -g NSScrollAnimationEnabled -bool false
defaults write -g NSWindowResizeTime -float 0.001
defaults write -g QLPanelAnimationDuration -float 0
defaults write -g NSScrollViewRubberbanding -bool false
defaults write -g NSDocumentRevisionsWindowTransformAnimation -bool false
defaults write -g NSToolbarFullScreenAnimationDuration -float 0
defaults write -g NSBrowserColumnAnimationSpeedMultiplier -float 0
defaults write com.apple.dock autohide-time-modifier -float 0
defaults write com.apple.dock autohide-delay -float 0
defaults write com.apple.dock expose-animation-duration -float 0
defaults write com.apple.dock springboard-show-duration -float 0
defaults write com.apple.dock springboard-hide-duration -float 0
defaults write com.apple.dock springboard-page-duration -float 0
defaults write com.apple.finder DisableAllAnimations -bool true
defaults write com.apple.Mail DisableSendAnimations -bool true
defaults write com.apple.Mail DisableReplyAnimations -bool true

To undo the changes, paste this into the terminal:

defaults delete -g NSAutomaticWindowAnimationsEnabled
defaults delete -g NSScrollAnimationEnabled
defaults delete -g NSWindowResizeTime
defaults delete -g QLPanelAnimationDuration
defaults delete -g NSScrollViewRubberbanding
defaults delete -g NSDocumentRevisionsWindowTransformAnimation
defaults delete -g NSToolbarFullScreenAnimationDuration
defaults delete -g NSBrowserColumnAnimationSpeedMultiplier
defaults delete com.apple.dock autohide-time-modifier
defaults delete com.apple.dock autohide-delay
defaults delete com.apple.dock expose-animation-duration
defaults delete com.apple.dock springboard-show-duration
defaults delete com.apple.dock springboard-hide-duration
defaults delete com.apple.dock springboard-page-duration
defaults delete com.apple.finder DisableAllAnimations
defaults delete com.apple.Mail DisableSendAnimations
defaults delete com.apple.Mail DisableReplyAnimations

Mac OS X also has dialog boxes, such as the ‘Save As’-box (CMD+SHIFT+S) or the ‘Print’-box (CMD+P). You can tweak the speed at which all of these boxes appear by using these commands:

Instant:

defaults write NSGlobalDomain NSWindowResizeTime .001

Fast:

defaults write NSGlobalDomain NSWindowResizeTime .1

Default (0.2 seconds):

defaults delete NSGlobalDomain NSWindowResizeTime

1 = 1 second. To see the difference you have to re-launch an app such as Terminal and summon a dialog box by pressing CMD+S (‘Save’) for example. You can find more command-line tweaks in defaults-write.com