When reading code that is a one liner and is wide enough to scroll, the Mac's scrollbars that appear is too big makes it hard to read the code, that is behind it.
It's not impossible but for UI its not good.
What can be done to address this problem?
NOTE: This might not reproduce on othe people's macs. I am using a Magic mouse with a 2011 iMac running Mac OS X 10.8 Mountain Lion.