For many students, difficult projects and misunderstandings sap the fulfillment from completing those projects. The endgoal, when this happens, no longer has anything to do with the process of learning; instead, they just aim to finish the work, usually as quickly as possible.
It's like doing a puzzle. When frustrated, students becomes so fixated on completion that they lose the necessary patience it takes to finish the puzzle, jamming pieces together until something resembles a finished product. Perhaps the biggest injustice here: the student won't look back on that finished picture with pride.
Learning is not just about finishing the puzzl...