It is quite hard to become rational as humans are emotional beings. Sometimes, emotions will take over rationality in making decisions. This is why people struggle to make wise decisions.
Reason needs axioms (beliefs) to build a rational discourse, and without emotions, it is impossible to choose a limited set of starting axioms to begin making logical inferences from.
I agree with the person above who said being rational is about making post-hoc rationalizations. We know by cognitive science that a majority of explanations are build that way: after observing facts, we intuitively develop a story that is consistent with our expectations about the fact, as well as with our preconceived beliefs. "Being rational" in this context would be limited to reviewing our beliefs when these ad-hoc rationalizations become inconsistent one with another.