I think this basically comes down to the same reason it's so hard to forecast the weather: there's way too many data points to consider to do anything other tha

I think this basically comes down to the same reason it's so hard to forecast the weather: there's way too many data points to consider to do anything other than make a well educated guess. "Irrationality" comes down to the ability to accurately decide that we have considered all relative data points and determine what is the best decision, and then prove that this decision hasn't been made. Consider game theory, the best example of "look how illogical all these humans are lol!" Every game is created with a very specific set of rules, most of which are very clean and specific. The pirate game doesn't consider how many children a pirate has to feed. The prisoner's dilemma doesn't account for social factors that might cause the prisoner in question to feel the system is already intentionally rigged to harm them no matter what their choice. All the "proof" of how illogical humans are in their choices has to be extrapolated away from all the life that humans have to live. TL;DR- I agree. People are "irrational" in the sense that nobody is ever really able to consider all the factors contributing to a real human's decision tree, but we all love to tell someone else that they're doing it wrong and we know better. Look at all this proof I have that you're being irrational (read: stupid) and you should be doing it better.