Felicia has issues accepting the spiritual side of the Adeptus Mechanicus - particularly the Weakness of Flesh. Despite her being a superior engineer and scientist, it took her a very long time to become a full Techpriestess and later Magos (though there might have been some subtle nudging by a certain Inquisitor - pure speculation of course). Despite becoming a Magos, she retained her emotional, irreverent attitude and a particular fondness of good food.