Ways to manage something like a 'work-life balance'? According to a recent international study on work-life balance within academia


  "a majority of researchers and scientists had conflicts between their work schedules and personal lives at least two to three times a week."


Nevertheless, 


  "about 60 percent of scientists were happy with their work-life balance. The rates for women were lower, at 52 percent."


I wonder what differentiates these 60 percent 'happy people' from the remaining 40 percent. What do you think are good strategies for a healthy work-life balance? How do you balance your academic work/life with your personal life?
Disclaimer 1: I know the two worlds : academia and the outside world ;) I worked in public and private universities, and in a consulting firm.

Disclaimer 2: I can only speak about life for people involved in theoretical areas, I know that science involving living things / big experiments has real constraints.

I heard a lot of people in academia complaining about the conflicts between their work schedules and personal lives (me included, because I'm grumpy). But we have to face it, most of the time there is nothing to complain about it.


"I have a deadline today at midnight" : I do that all the time, but the calls for papers are out several months before the deadlines, so the problem here is planning, not the nature of the work.
"I have to finish this grant application before midnight" : hum, grant applications and conferences deadlines seems to be of the same kind.
"It's 3 AM, I just got that email that needs an answer" : I don't think this email is that urgent. An BTW, if something is really urgent, phone still exists for that matter.
"Someone (supervisor, head of the team, dean, etc.) wants me to work more/at night/etc." : Slavery has been abolished. If you have good results, the thing is that in academia you are master of your schedule.
"I cannot stop thinking about that problem" : yep, here this is true, we bring our work everywhere. If a researcher cannot live with that aspect of the work (which can be quite stressful), then he should probably consider finding an other job.


My point is that working in academia is working in one of the most flexible field. 
This is where there is a big difference with the "outside world". 
This flexibility is the problem: many people have difficulty dealing with it, and thus are giving themselves very strong constraints, so strong that they cannot handle them.