A good program should look like AK47 :
Easy to use (configuration, settings, functions described definition) , a simple structure (low coupling, modular, a unit) , easy disassembly (mounting deployed, unloaded, with little migration disorder) , never stuck (known traffic conflict resolution ) , low failure rate (or unknown may arise Bug) , adaptability (to consider more environmental factors) , high reliability (no incomprehensible "pause" operation, the execution results in line with expectations) .