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1.
Exclamation of which many forms exist (i.e. you fail, you fail it, you suck at life), used after the subject has failed at performing an easy, simple or mundane task.

If said straightfaced and/or casually, the effect can be greater than that of other, milder insults. However, its use and effectiveness depend heavily upon timing.

Conversely, "I fail at life" can be used to acknowlege one's own failiure.
(Person A proceeds to open their front door, but in doing so slips and falls, causing them to wipe out on their front steps.)
Person B: "Wow. You fail at life."
by The J-Spot January 16, 2005