If your OS X system is acting flakey, checking out the log files is a great place to start your exploration of what is going wrong. Here is where to find your log files in OS X.
Like most operating systems, OS X has a ton of stuff running that is hidden to the user. Examining the constantly updated log files is a great way to tune and debug your system.
The quickest way to get started is by opening the Console application found in OS X 10.5 and later. This can be found through Spotlight or through the Applications -> Utilities folder.
Tens of hundreds of log files will be visible. Here are a few good ones to start exploring…
system.log describes issues regarding your whole system. DNS, networking, and Adium messages frequently appear here for me.
mail.log is occasionally useful when trying to get the Mail application straightened out.
CrashReporter logs are very important in debugging any crash within a specific application.
This is just a few of the log files that are being updated currently on your system right now. Console is a great tool to view them. Enjoy exploring the inner workings of your system.