Proving lower bounds for complexity (defined in terms of resources needed) of problems is known to be hard. Lower bound on a resource is the minimum amount needed to solve the worst of the instances of a problem. Hence usually worst case analysis is needed to prove lower bounds. The intention of such worst case analyses is mainly to install signs to control traffic of exploration for saving energy and being effective.
Such effort should not be confused with immature and dumb "but what ifs". Immaturity is usually flagged by non-productiveness of thought process. Dumbness is hard to be flagged especially because it's not as penalizing as immaturity for surviving.