I learned British English, but I work exclusively with Americans. I'll often say "Fat lot of good X did for us", and I get confused looks from others. For example, the other day, I said "I think we should have had them take the web development course; fat lot of good the algorithms course did for them" and people have no idea what I mean. A coworker told me that what I'm saying sounds like what someone British would say, and I'm not sure how to Americanize this statement.
First: Am I using the term "Fat lot of good" incorrectly? Second: How should I say this in American English?