I think if you're trying to make a choice yourself then making it sound silly is a good way to take the emotion out of the decision.

Another way I've seen people reason over things like this is in terms of an MMORPG/ARPG. 'You need to invest in your character to get stronger to beat the next boss. That will pay back in X amount of time, but if the value of the loot drops too much in that time then it's not worth it.'