Have you ever faced a situation, where you have looked into price, quality, comfort, convenience and so many attributes but you bought something because you felt like buying and there was no rationale? or did you decide on something and started looking for the reasons later?

What is a rationale at one point in time looks so irrelevant at other times. What we think is a rational decision can also be driven by our subconscious.

Decision making process is always based on a rationale, why and what circumstances are pushing you to take a decision of your choice. You look at the alternatives available and evaluate them.  Final choice is made on the basis of which alternative pushes you to reach the desired goal.     The reason why you make a decision is more circumstantial.  It is only that which is making you move towards what you want.  After a certain time period if you look at the reasons you explicitly stated for your choice appears to be name sake.  If you are in the same situation again or your friend is in a similar situation, your rationale would have changed.  The earlier rationale looks absurd and irrelevant.  These circumstances at that point in time were like a conspiracy driving you towards the end goal which you desired.  This clarifies that there is something which is beyond your conscious mind, which is driving things to a reality. Is it not the subconscious mind?   Here the subtle desire you have forces you to think of all the required circumstantial evidences to make your choice.
I have worked with many of them in the decision making process with the help of a decision matrix.  Listing all the alternates and choosing one on the basis of priorities. It is a complete rational process where every priority is explained with a reason.  Then the reasons are weighed to come out with the best possible decision. However, in this situation also, the subconscious makes way to choose only what it desires, and the reason becomes irrelevant and immaterial.
The modern thoughts and concepts in management is about rationalizing and making things more structured, with in  limits and putting ourselves in a frame of mind.  However, modern thought does not completely establish that intuitive decision making does not work.  Most success happens with intuitive decision making.  Even if we observe certain decisions as rational, the subconscious play in each decision cannot be ruled out.