Me thinks this is a rant, so moved to the Rants and Raves section.
Errors can happen due to any number of reasons, i.e. incompatible apps and themes, corrupt files, dropping water, etc. In many cases, the errors are caused by operator error - doing something you should not do.
In the case of error 606, that is a java error. What causes it, I do not know. You can go here for more information:
KB23954-"App Error 606" is displayed on the BlackBerry smartphone. The resolution appears to be to try a battery pull to see if that corrects it. If not then you will need to reload the OS.
In any case, that is no excuse for not backing up your data regularly, especially if it is important to you to keep.