“Journalists often ask me when I go to the field, ‘What do you expect to find?’ And my answer always is, ‘The unexpected,’ because we’re just looking at the tip of the iceberg; we’ve just scratched the surface.” -Donald Johanson
Imagine you wanted to know what your acceleration was anywhere on Earth; imagine that simply saying "9.81 m/s^2" wasn't good enough. What would you need to account for?