Making solutions without considering efficient usage of resources.
Focusing on solving the problem at hand rather than being distracted by external contraints irrelevant to the problem.
One must resist the urge to be efficient when coming up with a solution. The tendency towards efficiency might have various root causes.
Especially when people with an academic background try to come up with the most elegant solution on the first try, they tend to have a sense of pride about that too.
Why would you want to come up with the best implementation of your solution before you have any evidence that it will work? If you have enough confidence in your ability to change the implementation, make something that works, test it in real life, and then optimize it.
Principles are not rules, but guidelines; following them blindly tends to make the implementation worse. DRY could be a vicious one.