I was a bit skeptical at first, but it really helped: After years of concentration problems, I received the advice to keep a happiness diary for 5 minutes every evening in order to gradually direct my inner focus to positive events. I wrote down the three best moments of the day and took some time to relive them in my mind's eye. The effect is amazing. I now sleep much better, start the day more relaxed and am less likely to be distracted by minor inconveniences.

So a positive mindset really does seem to do quite a lot to us. For me, the effects are now practically comprehensible. I make fewer careless mistakes and stay more calm in stressful situations. Both circumstances have a very strong impact...