Having to tell my team that our product, their baby, had to be rewritten (because our competitors were gaining on us and we had accrued too much tech debt: new features took forever and the result was slow performance wise) and then motivating them to work on that rewrite with the same enthusiasm as the old product. There were over 200 people working on it and it almost went wrong because a lot of people kept trying…
What motivated you to rewrite it rather than fixing the debt in the old product?
It was a different time: the product was a combi of perl, php, c++. And then the business world, at least here, went over to java backends.