zlacker

It is what we seem to call the 'unknown unknown'. Basically something popped up that was not planned for and now you need to research/fix/qa and shove that in. Even our 'known' bits are always underestimated. Because many people are hopeful and willing to 'try harder'.

Heck I personally just did this. I scoped out a story. Then realized I had underestimated it because there was at least 2 tech stacks in the thing I had not used much. So I had to basically drop what I was going to do and figure out some PoC on that. THEN I could write my code.