By the time (the Leaning Tower of Pisa) was 10% built, everyone knew it would be a total disaster. But the investment was so big they felt compelled to go on. Since its completion, it cost a fortune to maintain and is still in danger of collapsing. There are no plans to replace it, since it was never needed in the first place. I expect every installation has its own pet software which is analogous to the above.
Computer / technology / science
Quotes, by Guy Kawasaki