A log level or log severity is a piece of information telling how
important a given log message is. It is a simple, yet very powerful way
of distinguishing log events from each other. If the log levels are used
properly in your application all you need is to look at the severity 
first. It will tell you if you can continue sleeping during the on-call
night or you need to jump out of bed right away and hit 
another personal best in running between your bedroom and laptop in the
living room.