There is something about present positive ...

Shawn Achor says in his TEDx presentation The happy secret to better work: "If you can raise somebody's level of positivity in the present, than their brain experience what we call 'A Happiness Advantage', which is, their brain while positive performs significantly better than it does in negative, neutral or stress. Your intelligence raises, your creativity raises, your energy level raise. Dopamine that floods our system during happiness causes two functions: not only it makes us happier, it also turns on all the learning centers in our brain."

Let's train our brain to natural positivity.
Why don't you write down one positive experience that happened to you during the day. Every day.
Or send one positive and thankfull email to one of your co-workers. Every day.