Anytime they start indexing or re-indexing a huge code base in a "background" thread, they end up locking the machine to varying extents. Linux is not as bad, as it only tends to lock up instances of the offending application... But that maybe because the Linux PC is a beefy workstation. OS X is on a much less powerful MacBook Pro, and freezes tend to lock up the whole system, or at least most of the other apps, especially Chrome.
I've also had problems with Chrome, and especially Flash, on OS X. Spinning beachballs on every page load. Click-to-flash was such a lifesaver, but I can now sorta see why Steve Jobs wanted Flash dead.
The spinning beachball has grown to be a frequent source of rage for me over the last 5 years. I'm surprised nobody else complains about it more. Maybe it only happens for heavy Java GUI-based apps?