I work 80% and have been doing so for the last 5 years. In Sweden you have that right until your child turns 8 years old (so until they've finished their first year of school), with reduced pay of course. This lets you be available to pick up your kids from school when they still have very short school days.

I rarely play ping pong or do non-work related stuff at work now, because I feel I want to make the most of my working hours. I go home around the time I often get a slight down time around 15:00 anyway, so I feel I'm very focused when I'm at work.

I think I will have a hard time adjusting back to 100% when my youngest child turns 8, but I know people who have negotiated down their working hours to play more video games so it will probably be fine.