How many GB's of RAM do you have installed in your MacBook Pro? Mountain Lion has been shown to be more memory intensive than previous versions of OS X and really requires "at least" 4 GB's of RAM to have any speed in working at all. And more RAM than that really speeds things up. This is at least one possilbilty to consider.
Hope this helps
Try running Repair Permissons from Disk Utilities.
Also did you install the update from Software Update? You might try installing the 10.8.2 Combo Update which will just install on top of what you already have. Then run Repair Permissions again.
My experience with the Combo update is it sometimes fixes issues from the 'Delta' update which is usually used in Software Update. I always install a Combo update manually.
A delta update updates the previous version of Mac OS X only. A combo update updates any version of Mac OS X since the last major reference release, such as Mac OS X v10.6 or 10.7.
For example, the Mac OS X v10.7.5 delta update can be installed on Mac OS X v10.7.4 only. The Mac OS X v10.7.5 combo update can be installed on Mac OS X v10.7, 10.7.1, 10.7.2, 10.7.3 or 10.7.4.
Reference to the above is here.
I am quite new convert from windows to mac and relatively ignorant mac, trying to get used to it with every use.
I bought Macbook Pro running 10.8.2 2.5GHz with 4GB about half a year ago. This is my first Mac and I got impression that it is much faster and better than windows. However, it turned out that it is not so fast after all. It is relatively very slow when starting up, opening applications and waking up...similar to what others said. Not only that, it seems that it is eating memory no matter how much you provide.
I installed Adobe Creative Suite recently and with 4GB I was loosing all memory in a short time. Basically, within a minute or so, I would be running out of the RAM.
Few days ago, I upgrated memory to 16GB and guess what?! Running Photoshop and Indesign together with usual suspects (Firefox, Mail and Finder) would easily eat up over 8GB of RAM. Is that normal?!
Not only that, I realized that immediately after the start up of the system it eats up between 2.5 to 4GB. Now, what should I do?! Your advice and inputs are highly appreciated...thanks