ו) וְעַתָּה נַפְשֵׁנוּ יְבֵשָׁה אֵין כֹּל בִּלְתִּי אֶל הַמָּן עֵינֵינוּ:
אבן עזרא על במדבר פרק יא פסוק ו
נפשנו יבשה - היא הנפש המתאוה הנטועה בכבד:
I do not recall the source, but it is asked how the Jews could possibly complain about the Mon considering that it would taste like anything they desired. And it is answered that the Mon only tasted like specific foods when the intent that it taste as such was held in one's mind. Therefore, the Jews complained: "Isn't it enough that we must have kavannah when we daven? Now we must have kavannah when eating as well?!"
This is medukdak in the lashon of nafsheinu. The nefesh is the seat of emotion. The eating of the Mon was an essentially intellectual activity. [Chabad-style Deveykus?] The Jews objected to having eating, an essentially sensual and emotional activity, transformed into an essentially intellectually and mind-focusing activity.