Another Lubliner Rav vort (the last one was pretty good, wasn’t it? I'm getting addicted):
Hashem told Moshe not to be concerned lest Aharon have bad feelings about his being appointed as leader. To the contrary, Aharon was on the way to happily greet Moshe, “V’ra’ach v’samach b’libo.” The Midrash comments that had Aharon realized that the Torah would write such words of praise about him, he would have gone out to greet Moshe with a whole parade!
Everybody asks: you mean Aharon was out for the glory? He would have behaved differently had he known his deeds would be recorded for posterity than he behaved in private?
R' Meir Shapiro answers: Aharon was not at all out for the glory. To the contrary, Aharon did everything in his power to conceal his greatness from people. It would have been easy for Aharon to walk around with a big smile, showing everyone how happy he was to greet Moshe, proving to the world that he bore no ill will, that he had no trace of envy in him. People would walk around saying, “Look at that Aharon – such a sterling model of perfect behavior.” But that was not Aharon’s way. “V’ra’acha v’samach b’libo” – Aharon will rejoice in his heart. Aharon davka kept that smile tucked away inside, between Hashem and himself, and didn’t show off his true feelings to others, so as to avoid the lavish praise that would come from people noticing his exemplary midos.
Yet Aharon’s efforts were for naught. Not only did he get credit for being happy for his brother Moshe, for not having any jealousy or envy, but the Torah records for posterity the “samach b’libo,” the fact that he didn’t even want the public to know about it. Had Aharon known that acting privately would have attracted that much more attention from the Torah to his midos tovos, he would have arranged a parade to minimize the credit he received!
(The Midrash makes a similar comment about Boaz and Reuvain, but I’m not sure you can get this pilpul to fit those cases… It's too nice an idea to nitpick about such things.)