Rationality and Choice-making

What we commonly perceive of rationality basically agrees with the concepts that we discuss in class. For example, when we think of people who are regarded as rational, we typically attribute the person to make decision by thoroughly going over all the options and cautiously weigh the pros and cons of different options before reaching the final conclusion. This is the common explanation for the concept of expectancy value that we have talked about in class. To make what is called rational decisions, we are based on the formal calculation of net value, which is the product of the chance that a specific outcome will occur and the resulted gain if it does occur. To be a perfectly rational player, we will always choose the option with the maximum net value.
However, as it totally makes sense, there is no such thing as the perfectly rational decision and perfectly rational player in the real life. Because to achieve such perfect rationality, there are a few assumptions to be met which are unrealistic in our real world. First of all, to make such comprehensive and accurate calculations of net value, it requires us to have perfect knowledge, basically to know everything about how the world operates. This sounds utterly insane for people like you and me. We are humans and humans have limited capacity to learn. Perhaps our brain is plastic enough to make that amount of neuro-connections, the problem is our limited capacity of directed attention that prevent us from grasping so much information. The second assumption, equally absurd, is a single metric to measure the value of all things that you could possibly imagine. This is not an economic class, and the world is definitely not a simple economic model where everything is assumed to be measured with a single currency. There are so much that you can not measure. For example, try to give me a dollar value on how much you love your family, your dog, and Michigan football (right, a passion unknown to mankind, don't even dare to measure it!) Last but not least, is the assumption that our ultimate purpose in life is to maximize the net value. So wrong! We live life like party and who cares about the outcome (just kidding!) But there is some truth in it as we live to survive, on the evolutionary level, and to enjoy ourselves, on a more humane perspective, which not always depends on the outcomes and so-called net value.
This leads to my next topic: rational people might not be as happy, or even as successful as people who tend to follow their heart (mind actually). For example, my mom is a much more rational person that my dad. As my mom constantly worries about the sanitation of food when we eat outside (to provide a larger background, food sanitation could be an issue in China sometimes), my dad cannot care less. As she makes that calculation in her head on the net worth of eating her food compared to the potential damage the food could do to her body, my dad is already enjoying his food. As I always tell my mom, instead of wasting your time and energy (directed attention) on outcome you will never be able to know (imperfect information on food composition and body chemistry), why not just go ahead and enjoy like my dad? Like my dad always says, "you're not gonna die if you eat it."
This might sounds funny, but there's something significant about it as I now see it, because it is a pretty reliable instinct. Instinct doesn't come out of nowhere. It can be the essence of our previous experiences and the voice of our evolutionary progress. It is not to say we should unconditionally rely on our instincts, but instincts sometimes do speak some truth. A little instinct and some information-processing would be my recipe for decision-making.