If there are similar car crashes on the corner of 15th and Market Street on Sunday and Monday at 11:58 AM, would you bet money that there will be a similar crash Tuesday at the same time?
In software, once is an anomaly. Twice is proof. If I press that button and the program crashes, I might say “hm!” and wonder if maybe something else was going on at the same time. If I press the button again and the program crashes again, then it’s nigh on to a rock-solid certainty that there’s something hinky with that button code.
I wonder if that determinism — predictability — is what draws people to writing software as a hobby or a vocation. To quote Walter Sobchak, “there are rules.” And I submit that this is a big subconscious allure of the craft.