People aren't rational actors for a reason: Sometimes things are easy to argue for but aren't that great in practice. And so by following your heart instead of your head, you sometimes make seemingly illogical but objectively better decisions. And I think that there is a case to be made about how C++ is efficient in theory, while C is effective in practice.
And sometimes you make seemingly illogical decisions that end up being objectively worse decisions. The problem is that we don't really have a way to quantify our emotions usefully, which means we can use them accurately and are forced to allow for enormous amounts of error in our calculations when we provide any level of significance to them. That's why they are often seen as detrimental to rational decisions, not because they don't matter (obviously emotions do), but because including them sometimes leaves us no better off than flipping a coin (are the downsides really that bad, or is your fear of change in this instance vastly overwhelming the other considerations, and in an unwarranted way that you aren't entirely aware of?).