is always being rational, rational?

No, its not always rational to be purely logical. In some cases it may be in your interest to be more machiavellian. E.g. office politics.

Drawing on my own recent experience, being rational all the time is not always rational. I was recently rejected from medicine post-interview. Even when I was applying, I had my doubts and inhibitions but it seemed rational to apply as a straight A student, top of my college and enjoying working with others in my role as a student teacher. I love learning and exploring the workings of the human body and how its malfunctioning can be fixed through medical intervention. I have a strong work ethic, drive and determination to work hard and achieve the highest possible. From anyone, including my parents' and teachers', perspectives, medicine seemed the perfect course to apply to. So I applied because it was rational given my track record. But it never sat well with me. I could and can never pinpoint an exact rational reason or requirement that I did not meet that would mean I shouldn't apply, or I should be rejected.

It was only after rejection that I learned what a gut feeling was - I always had a gut feeling medicine is not right for me and still can't really point out why. But I just know that it's not the path written for me. Speaking of written, I believe that fate exists and that whatever is meant for you will happen despite how hard you may try to achieve something, it still may not happen because it's not fated for you. On the whole, I would consider myself a rational person because I make decisions based on solid facts and knowledge, but being rational may not always lead you to the right path. Sometimes, in those major decisions and life-changing moments, emotions and belief in fate, though they seem irrational, are rational. As humans though, it's hard for us to comprehend this. It's hard for me to explain why I wasn't upset by the rejection.

I don't know if I just answered your question at a completely wrong angle or if I even made sense so forgive me in advance :P