Photoshop :: Significant Lag And Small Glitches In CC?

I was running CS4 before moving on to CC and never noticed any interface lag or uncommon issues. In Photoshop, I am encountering significant lag in using certain tools, e.g. the lasso tool. A common scenario: I select the lasso tool, begin to make a selection with my wacom pen and... nothing happens. Everything else is inaccessible for a few moments until a message box appears saying no pixels have been selected. From there, things may or may not work like normal. Today, the button tools in Photoshop were giving similar lag responses (even just using my trackpad, no wacom).
 
As far as small oddities go, the other day I was working in Illustrator and made a simple line stroke. When I moved a point with the direct select tool, it switched to a rounded corner on only that end point (not the other), though no rounded corners were selected in the stroke box. Toggling the rounded corner button turned on rounded corners, then returned to a single rounded corner. Moving the end point with the direct select tool again would make the rounded cap disappear.
 
I've checked my CPU usage while I work and it is very low, and I'm not working on large files (less than 10mb). Though I don't recall any more specifics at this time, the feeling I keep getting, misplaced or not, is that CC isn't stable.
 
I'm on the Retina Macbook Pro, 2.3 GHz Intel Core i7, 8 GB 1600 MHz DDR3 Ram, version 10.8.4.