On the Census there is an X next to my ancestor’s name! Why?

“United States Census, 1940,” database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:3QSQ-G9MY-QW27?cc=2000219&wc=QZX5-GFW%3A792575201%2C793080701%2C792713801%2C951549501 : accessed 6 March 2021), Texas > Austin > Justice Precinct 3 > 8-9 Justice Precinct 3 SE of Gulf, Colorado & Santa Fe Railway (Sealy-Eagle Lake Branch) and W of Gulf, Colorado & Santa Fe Railway (main line); Immaculate Conception School, Sealy (part), Sealy Hospital (Dr. F. W. Hoover, Owner) > image 10 of 37; citing Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 – 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012.

This is an easy one! The X is who the informant was. Sadly this only works for the 1940 census as that was the only census that recorded the informant. Even so this can tell you a lot of about the family, who was home and what they called their family/roommates. What interesting information have you found in the 1940 Census?