Setting and maintaining work boundaries can be beneficial to our physical and emotional health.  By creating a consistent work schedule and leaving at your designated time, it sets a starting record for consistency.  Leaving work on time allows for family, exercise, healthier eating, etc.  
It's a common thought we have that we "must finish this one thing" before we leave for the day.  Time management throughout the work day and week can help facilitate this feeling.  However, regularly staying late and overworking can lead to physical symptoms, anxiety, and burn out.  Physical symptoms can include, but are not limited too: headaches, spaciness, confusion, tingling sensation, restless leg syndrome, clenched stomach, dizziness, etc.