Costs including time and money, which have already been expended.
A common fallacy is the sunk cost fallacy, where people continue to do something because they have already invested time and energy in it: They persist, even though there is no realistic payoff at the end anymore, or there is little chance the project can be finished. This is a common story in Kickstarted titles.
Dev wants to make a game. Dev starts developing the concept and generates all kinds of great ideas for how to make the game better. Dev raises money on Kickstarter to fund development. Development goes sideways: It takes a lot more time and money than anticipated, and the developer ends up stuck way behind schedule. If the game can be finished, largely as promised soon, continuing development can be a good way forward, but often this story ends up at; dev can?t afford to work full-time on game anymore but will work part-time until it is done. The problem is after 3 virtually full-time years the game is not even half-way finished. It is admirable to want to fulfill your commitment, but at some point it is better to own up to your mistakes and, if possible, try to find some way to reward your backers.
This War of Mine