We find old routines comfortable

Habits are comfortable. When we're stressed out, we tend to fall back on our old habits for two reasons:

• The brain likes to know what is going to happen next. Routines are situations that have occurred often enough that you know exactly how events will unfold.
• The brain wants to spend the least amount of energy on any particular activity. The less time you spend thinking about something, the less energy your brain uses on it.