Wet floors

An amusing anecdote from the first time I met a good friend of mine: He was writing some code to dedupe files on his fileserver and needed to pull some logic out of a loop to run it somewhere else. He copy-pasted it rather than abstracting it out into a function, saying "oh man, I bet this is going to come back to haunt me". Literally ten seconds later he changed the logic in the body of the loop without changing it in the place he'd copied it to, hitting the exact problem he was worried about.

I think of those situations as wet floors, after a time I was in a KFC and I saw the workers behind the counter skidding around on an oily floor right next to the deep fryers. I spent a long time thinking about how one of those kids was going to slip and put their hand in boiling oil before I even realised I could do something to prevent that outcome. Of course, when I went up to warn them the response was "oh, yeah, that is dangerous". I'm fairly certain they didn't actually clean the floor.

It occurs to me that this is a consistent pattern in software development and elsewhere: you see a problem just waiting to happen, and you notice it but instead of doing something you say "that's going to be a problem". Later on when it is a problem, you can even say "I knew that was going to be a problem". Though that is a deft demonstration of analytical and predictive ability, it could perhaps have been put to better use.

It sometimes seems like the drive to understand things can be so strong that you lose sight of the underlying reality. "I understand how this works" can be so satisfying that it makes "I should change how this works" unnecessary. Or perhaps it's just that understanding is always a positive; it's often not that difficult, and it feels good when you do it. Whereas acting in response to your understanding can be a lot of effort and doesn't always work the way you want.

There is also an element of confidence. Something you believe in a consequence-free way is very different from something that has serious costs if you're wrong. I've heard it said that the hardest job is being responsible for the Big Red Button. When you press the Big Red Button, it brings everything to a halt and costs hundreds of thousands of dollars, but not pressing it costs millions, maybe destroys the whole company, and definitely your career. It must take enormous confidence to press that button when necessary.

A related technique that I quite like is the pre-mortem, where you pretend something has gone wrong and explain why you think that was. What's considered powerful about it is that it removes the negative stigma from predicting failure, but I think there's something else as well: a pre-mortem directly connects your knowledge of failure to the reality of failure. That is, it forces you to imagine the eventual result of "this is going to be a problem": an actual problem.

Perhaps all that is required to defeat wet floors is to drive up your own confidence in that belief, or associate it strongly enough with the actual failure it predicts.