We’ve all been there: wanting to scream but taking the high road and plastering a smile on our faces instead of revealing our true feelings. But will that innocent act negatively affect your mood?

Smiling may alter the first impressions you make for the better, but the act of smiling itself may negatively impact you. A recent study by a business scholar at Michigan State University found that people in customer service positions who force smiles often end up worsening their mood and productivity. The opposite was true for employees who smile as a result of positive thinking.

However, the findings also suggested that using positive thoughts for deep acting could result in making people feel more like actors than their true selves. To everyone who works in a service-related job: Do you find that the frequency and reasons behind your smiles alter your mood one way or the other?