One of my new coworkers just invented the word sustenation. (Yes, it's in the OED, but it's quite rare. I think she independently invented it.) You'd think the red squiggly line under it would have tipped her off that something was wrong. The weirdest part is that she replaced the perfectly cromulent word sustaining with sustenation because she thought that sustaining was nonparallel in context. I guess it sort of is (the other words in the list are noun, and this is a gerund, which is sort of a hybrid of a verb and noun), but it doesn't warrant that.