The Dreaded Spinning Wheel
Honestly, I have never seen so much dreaded spinning wheel in an upgrade than in Mountain Lion...what's up with that? Is it because the upgrade was intended for the latest processors such as the I7? After using Firefox for say half an hour, every action initiates the dread spinning wheel despite having the maximum Ram installed in my machine. I just restart Firefox or the machine to resolve.
MacBook Pro, OS X Mountain Lion (10.8.1)