Rhaegar Targaryen was a pretty smart man, He read alot and was a very intelligent and determined person, Commonfolk loved him, he was a respectful and honorable man, according to Ned.
So how is it that, Rhaegar Targaryen a person that is very smart runs away with a stark girl without thinking of the consequences?
Since he was the Prince and soon to be king, couldn't he somehow manage being with Lyanna stark without starting a war and losing his own life in the end?
What was he really up to? did he actually love Lyanna stark or was he up to something else?