I have found all of my dad's direct ancestors in the 1940 Census, as well as a few collateral folks too. On the other hand, I have found only my mom's mom and maternal grandmother. I had no success finding any of her father's family or the rest of her mother's family. The problem comes from them being mill workers and moving often. It's difficult to find the correct address, especially when they were living in smaller towns without online city directories. I'd browsed through about eight EDs looking for my mom's dad and his family to no avail.
I'd meant to call my Great-Aunt Ree earlier in the week for help, but got side tracked with searching for my dad's people. Today I asked my mom to call Aunt Ree, to which she responded that I should call her. She's making me work on my social skills... sigh. So I called her and very quickly realized why I couldn't find her or her brother, my Grandaddy: I was looking in the wrong city. I thought that she's said before that the family was in Greenville, SC in 1940, but today she said that they had been living on Greene Street in Greenwood, SC.
I chatted on the phone with her while I browsed the two EDs that contained Greene Street. I learned that they moved to Greenville in '42 and that her father, who died in '47, had never owned a car. Oddly though, he had driven a taxi cab for a few years. After the family moved to Greenville, they often visited family still in Greenwood by riding the P&N Train back and forth. Her parents had worked in mills in Greenwood and for other mills in Greenville that were all owned by the same company. She can remember so many little details about her childhood and was more than happy to tell me everything she could.
Unfortunately I did not find her on Greene Street, so questioned her some more. Before that they had lived on Pelzner. And that's where I found them: 515 Pelzner Street.
I'm really glad that I called my great-aunt, otherwise I probably would not have found this family until an index became available. And it looks like South Carolina is going to be late on the list. So do yourself a favor: if you're having trouble finding your family and there's someone you can ask for help, do so.