His arrogance would be his downfall.
Rodney McKay was arrogant and everyone knew it.
However they didn't know that all of his boasting, preening covered the internal fear that he wasn't good enough, couldn't do it.
All he thought he wanted was their respect, their friendship.

Something real and true, to know that people that didn't just want him because he was the smartest man in two galaxies.

What he didn't realize that what he truly wanted was someone's love

It was right in front of him.
And he was going to loose it if he didn't open his eyes.