It seems like a joke when you are told to think about beautiful things and good things will come.
Thing is this is not a joke!
With every worrying thought you have planted a seed for more worry. For every angry thought you have evoked anger and turmoil within you that shows more on the outside then you may think. We all have bad thoughts it is almost engrained in us to victimise ourselves one way or another or put others down because we don't understand.
But today when the bad thoughts come, and they will come, turn them into a positive. You will be suprised at how effective this is. Try it. Right now!