Fit in or fuck off (or FIFO) is an expression used unofficially within organizations. It is a controversial human resources philosophy whereby the employee is expected to rigidly conform to the prevailing organizational norms or get fired. It is related to the "Last hired, first fired" concept. FIFO more commonly stands for first in first out so the casual observer may confuse it with that meaning.
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Fit in or fuck off Wikipedia(Text) CC BY-SA