Here is my story from a project in Sweden that I will never forget.

It was 11 PM in Stockholm. I was finally in bed after two hard weeks installing the ticket system for the Arlanda Express train. Everything was working perfectly.

Then, my phone rang.

My boss in Spain was very nervous. He had forgotten to change the "subnet mask" of the X.25 gateway for credit card payments. He was afraid of a big financial penalty. He asked us to go to the airport immediately, change the mask, and not tell anyone.

We were exhausted and did not think clearly. We forgot to ask the most important question: “If the mask is wrong, why are payments already working?”

Because of the pressure, we drove through the snow to the station, changed the configuration, and left. We did not perform any tests.

At 5 AM, as I got home, the phone rang again. It was the railway's Head of Technology. The station was open, the morning rush had started, and no credit card payments worked.

I explained that we had changed the subnet mask. He didn’t get angry; instead, he was surprised. He told us that he had also seen the problem earlier and had secretly changed his own system to match our "wrong" configuration so the launch would work.

Both of us made secret changes to "fix" the problem, and that broke everything.

What I Learned:

• Transparency is key: If we had communicated, we would have known the other side was already updated.
• Don’t work when exhausted: When you are tired, you miss the obvious.
• Always test: There is no such thing as a "small" change in a complex system.
• Question the "fix": If the system is working, ask why before you change anything.

Here is my story from a project in Sweden that I will never forget.

It was 11 PM in Stockholm. I was finally in bed after two hard weeks installing the ticket system for the Arlanda Express train. Everything was working perfectly.

Then, my phone rang.

My boss in Spain was very nervous. He had forgotten to change the "subnet mask" of the X.25 gateway for credit card payments. He was afraid of a big financial penalty. He asked us to go to the airport immediately, change the mask, and not tell anyone.

We were exhausted and did not think clearly. We forgot to ask the most important question: “If the mask is wrong, why are payments already working?”

Because of the pressure, we drove through the snow to the station, changed the configuration, and left. We did not perform any tests.

At 5 AM, as I got home, the phone rang again. It was the railway's Head of Technology. The station was open, the morning rush had started, and no credit card payments worked.

I explained that we had changed the subnet mask. He didn’t get angry; instead, he was surprised. He told us that he had also seen the problem earlier and had secretly changed his own system to match our "wrong" configuration so the launch would work.

Both of us made secret changes to "fix" the problem, and that broke everything.

What I Learned:

• Transparency is key: If we had communicated, we would have known the other side was already updated.
• Don’t work when exhausted: When you are tired, you miss the obvious.
• Always test: There is no such thing as a "small" change in a complex system.
• Question the "fix": If the system is working, ask why before you change anything.

javagoza said:

It was 11 PM in Stockholm

Make sure when you write your memoirs you call this chapter "It was 11PM in Stockholm.".... and don't forget javagoza  I want the movie rights to that Northern Africa Marijuana scheme you got tied up in.