In fact, subtle changes in programbehaviour and timing can cause them to appear unexpectedly. Some examples are.
实际上，对程序行为和计时的细微更改可能导致这些异常的意外出现。
2
Mr Bowling attributes Polaris's stronger performance to a crucial modification that allowed the program to adjust its strategy in response to its opponent's behaviour during a match.
By analysing someone's behaviour during a training period, a program called Busy Body can learn to tell what someone is doing and whether to interrupt him.