Sunk Cost Fallacy
Thousands of graduate students know this fallacy all too well. When we invest time, money, or effort into something, we don't like to see that investment go to waste, even if the task, object, or goal is no longer worth the cost. As Nobel Prize winning psychologist Daniel Kahneman explains, "We refuse to cut losses when doing so would admit failure, we are biased against actions that could lead to regret."
That's why people finish their overpriced restaurant meal even when they're stuffed to the brim, or continue to watch that horrible television show they don't even like anymore, or remain in a dysfunctional relationship, or soldier through grad school even when they decide that they hate their chosen major.