Some people just don't act rationality, including in their money management. There is nothing to fix here. You could say, "if they are unhappy at the end, there is something to fix".
Most rational people don't understand this because of the logic: you don't want to produce a future unhappiness.
Let's take a softer example: in a winter morning, how should you dress up?
Well, a rational mind would look at the weather forecast, open his window to feel the outside temperature and dress up accordingly.
But some other people won't care. The "effort" required to make the right decision is too high, the gain is too low, why care after all?
For those people, there are three outcomes possible:
1. they took a good decision without the information and will be happier than the rational guys, because they did not have to care about taking the decision and the outcome was good
2. they took a bad decision but still it was not worth the effort and even if they got a little cold during a few hours, they'll make it at the end
3. they took a bad decision which they must turned into bad enough consequences so that they should have cared (eg. they got cold)
And the best is that in category #3, a rational person would learn from what happened and avoid to reproduce it, but being irrational allows the person to not learn from its experience.
The conclusion to this is that since most of our decision making in everyday life is rational, it is hard to understand those who don't act the same way. Also we all are more or less rational, because that's what society forces us to be in respect of the others. But some topic, like how to spend money, or dress in the morning are left to one's freedom, and must not be controlled by some higher rationality.
Nothing proves us that the irrational outcome won't be better that the rational one. What if outcome #1 is the most realistic one?
