Let’s talk about plumbing, and customer service, and an experience I had recently with a company I won’t name. Overall the experience was good, but I don’t want anyone to get into trouble because they’ve misinterpreted what I have said here. (and if you’re wondering about the picture : the Olympic flame isn’t lit either).
A couple of months ago, our gas combination boiler failed. It refused to start and complained that the flue was blocked. I sighed because we’d had the bearings on the fan replaced last year. So I called the service company to get it fixed.
A couple of days later, I was working from home to let the service technician in. He was fairly young but identified a problem. Unfortunately, a new part was required, so he had to come back the next day. He came back, replaced the part, fired up the boiler and all looked good. The next morning, no hot water and a flue warning 
it was the weekend by this point so we got a senior employee, who identified an error in the replacement part (fitted the wrong way) and identified the original problem as a blocked inlet. 5 minutes to identify, 1 hour to dismantle the boiler to get to the blockage and put it back together.
He finished, switched the boiler off, and then made sure it fired when put back together. Problem solved.
So, what did I learn, and why am I posting this on a programming blog?
Firstly, a monthly fee means that I didn’t have to worry about callout or parts, which was great, and left me less annoyed than I might have been.
Secondly, your first fix might not be the right fix. It looked right and it passed the first test, but caused problems later on (at the next restart). Ever written the wrong test and thought the problem was solved? Threading has caught me out in that way before.
Thirdly, just because it passes the test, doesn’t mean the problem is fixed. The boiler fired easily when the case was open and there was more airflow, but didn’t fire when the case was closed. Ever had a bug that only appeared in production or in a system test?
Fourthly, experts will find problems quicker than rookies, but rookies still need to learn.
Fifth, sometimes the only way to fix a problem, even a small one, is to tear everything apart, blow on it, and put it back together again.
The second guy also said something that struck a chord, as I’ve been trying to do it myself : he was disappointed that the company didn’t send the junior out with him so he could pass on his experience so that he’d learn for next time. Apparently, the fault itself is rare, so it’s a good learning opportunity. For developers : fix your own bugs, as there are a lot of things apprentice developers will see in the first few years after they graduate that are rare enough not to come up in university but common enough to be real problems in the real world. For example,
trusting user input (and the related buffer overrun bugs).
So, what have you learned from other professionals?
