In my Introduction to Accounting Class and in my experience making Income Statements from account journals, I learned that P&L statements shows how well an organization is performing overall and how they allocate their resources and assets. For companies that are in the corporate level or in relatively large organizations, they will include as well their investing activities such as purchases of securities, assets, etc., and this shows what liquid & real assets they have, and it shows what do they invest in in retrospect.

my favorite formula is a combination between Vlookup and If functions because, in my experience helping my father making his Excel Database system, you can make a plethora of various types of systems that can compile & present data neatly.