What time is it?
Up until the late nineteenth century there was no way to agree on an answer. Every location had its own time- there were thousands of 'noons' in the US alone. The establishment of national railroads and the prime meridian finally gave a reason and a method for setting a common basis for understanding. Imagine a train timetable where you might arrive before you depart and providing you with no sense of duration. In 1884 a fixed location of 0 degrees longitude was established at the royal observatory in Greenwich allowing location and hence time to be defined precisely. From then on things made sense.
In thinking about marketing metrics it seems we're still in the late 19th century with hundreds to choose from and consultants promising to help find the right ones. Finance went through similar throes and ended up with one or two with cash flow being on everyone's short list.
It might be time to think about the ones that really matter at the end of the day.