Crossovers are inherently unnecessary. Even if they're not the result of corporate mandate or desperate ratings grab, the best that can be said of a crossover is that it provides two fanbases with a chance to play “spot the reference” and argue about which franchise was given more to do. The shows of the moderately anticipated Simpsons/Futurama crossover “Simpsorama” at least—like the Bart gremlin monsters that provide the impetus for said crossover—share some common DNA.