It can be extremely difficult to understand the cause of things like that. Some bugs only happen in combination with other bugs, on particular hardware, etc. In those cases, you really need other types of data so that you can try to find common denominators. Apport is a bug reporting system that fetches relevant data. The
ubuntu-bug command is even simpler. For instance, if you have a bug with Unity, you can press Alt+F2 and enter
It is beneficial if you can provide information about what you're doing if you can reliably reproduce it. In your case, I would try to press Alt+F2 and enter
unity --replace. If that helps, provide that information.
unity command provides a few helpful switches as well, such as --log, --advanced-debug and --verbose. Debugging skills are very useful, but you might want to start with something simpler.