When you click on the Start Menu there is some delay to display the contents , just for no reason. Effects are pretty though. The default speed can be adjusted with a quick registry entry.
The default value is 400. Set it to 0 and the delay is gone. If you are not able to adjust pick a number that suits your style and make the change.
[Start] [Run] [Regedit]
Go to HKEY_CURRENT_USER\Control Panel\Desktop
Modify/Create String value of Data type REG_SZ Named [MenuShowDelay]
Value Data: [Default = 400 / Adjust to Preference]
Exit Registry / Reboot