On page 49 of The Army Ground Forces: The Procurement and Training of Ground Combat Troops volume of the Official History of the U.S. Army in World War II is a table that shows how soldiers felt about their jobs. It shows that of soldiers assigned to the Infantry only eleven percent preferred being there. Of those assigned to the Air Corps on-the-other-hand seventy-six percent preferred it.
The table also shows that as of the end of 1943 seventy percent of the casualties were taken in the infantry while only five percent in the Air Corps.
Causation is not necessarily correlation in this case, but most people in the Army at that time realized being in the infantry sucked.