Someone at work used the expression "We'll do" yesterday. It's supposed to be "Will do," as in, "Could you open that account for me?" -- "Will do." No big deal, just interesting how people misunderstand things.
Another one, which bothers me a lot more for some reason, is "kitty-corner." It was originally "cater-corner," but is now usually "catty-corner" (http://www.dailywritingtips.com/the-post-office-is-kitty-corner-to-the-court-house/). The expression has nothing to do with cats or kittens of course -- apparently it bears some relation to the French "quatre," four, but I don't know how this led to the sense of "diagonal" -- but some people can't hear "catty" without thinking "kitty."
I think the phrase "can't win for losing" is a Southernism; in any case, my parents both used it, and I don't hear it much elsewhere. The one time that stands out to me was in Ann Arbor, when I heard a University of Michigan student say, "I can't win for trying." That attempt to use an unfamiliar expression fell flat -- it made no sense, and sounded kind of pathetic. "For" means "because" in this sense; you can't win because you're losing -- not you can't win because you're trying! Of course, it's kind of a silly phrase to begin with -- losing is not a reason for failing to win -- but it does express a meaningful sentiment: a sense of hopelessness, with no idea why one can't succeed.