Quickbase tasks are based on a five-day work week. For example, if Task 1 will take 2.5 days to complete and it begins on a Thursday, it will end on the next Monday at midday, and its successor task will start at that time. But say you run a 24/7 kind of shop. Your business is open on weekends, and you don't want Quickbase to skip them.
You can easily change the work week to include weekends if you want. In a project management application that uses dependencies, open the Field Properties page for the end date field and turn off the Work week is Monday - Friday checkbox.