One of the biggest problems at the supermarkets is how to manage waiting time at the checkouts lines as they can have a huge impact on the customers satisfaction. This study tries to understand what are the customers perceptions of the waiting time and how this influences their behaviors during and after a store visit. The crowding effect was also analyzed. A sample of 110 Brazilians consumers in Rio de Janeiro city was obtained through a quantitative survey. The finds suggest that, despite unsatisfied with the waiting time and with the personnel, consumers tend to prioritize price and location. They also suggest that some consumers tend to perform little acts of revenge during their shopping when they think the waiting time is unfair.