Being busy is good, it’s better than being unproductive. But when you become too busy doing too many things, your performance on all other task will decrease.
You must set limits if you want to be productive. The quality of your work depends on how well you do it, not how many active tasks you can juggle.
Don’t settle for subpar work and don’t subject yourself to burnout. Remember Parkinson’s Law: if you don’t set a limit on your available time, your work will expand to fill it all.
Draw a line around your life so you don’t let all the work consume all of your energy.