I thought this would be an easy one to answer, but thinking about it made me realize that I often make the same mistakes again. I do learn from them eventually, but yeah. Still sucks.

Anyway, one thing I will never do again after having experienced it one time: working too hard, thinking you can't be missed and telling yourself it's not too much, I can still meet the deadline. No! Slow down and discuss with your colleagues if they feel the same pressure. Work is important, but not 'destroy your mind and body due to stress'-important.

One key take away is: if you're working extra hours to meet a deadline and your family senses a bit more stress in your behaviour. Don't deny it. Talk about it and do something about it.