that's one on me

that's one on me

That is a mistake or joke that makes me look rather foolish. It's just normal gasoline? The guy down the road said it would clean my engine, charged me double for it. I guess that's one on me. I can't believe I fell for that—that's one on me!
See also: on, one
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

that's one on me

That's a joke at my expense, as in And after all that discussion they didn't show up-that's one on me. This phrase must be distinguished from that's a new one on me, which means "this is the first time I've heard of or seen that" (as in A checkerboard rug-that's a new one on me). Both idioms can be used with other personal pronouns (for example, that's one on you) and date from the early 1900s.
See also: on, one
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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