Being in a rush is counter-productive. It is stressful for the people doing the work and the quality of the work suffers. In software development that translates into an ever increasing amount of spaghetti code and an architecture of quick fixes which then leads to a slow down. This slow down then leads to greater time pressure, and the rush gets worse.
Real deadlines do exist, and sometimes out of necessity a team has to pull out all the stops and make a short-lived dash. The big problem arises when this mad dash is the normal state of affairs.