I've been noticing a lot of bugs in the Mail app, sometimes it randomly goes offline, doesn't fetch mail.
Some fonts seem blurry (i.e. Tabs in Activity Monitor). I'm not on a retina Macbook Pro.
Right click in a web browser and the text in the menu seems to have a white background instead of transparent... just looks a little weird.
All pretty minor, the Apps I use on a daily basis all seem to work. Sublime Text, Coda, Photoshop, Mozilla/Chrome/Safari, Steam and Xcode
Last night, while playing a game (7 Days to Die), I had 2 Kernel Panics (Kernel Trap). Its very possible that this could have been a hardware issue, but for now I'm blaming OS X (Only because I'm outside of apple care warranty...
). However I did install SMC Fan Control awhile back, reset the PRAM, now I'll just wait and see if it happens again.