How do you feel grateful during challenging times?

The feeling of gratitude for me is an ecstatic experience, beyond any "feel good" feeling on the face of the earth. 

It's impossible to feel sad, mad or fearful when we feel grateful.

It's a piece of cake to feel grateful when things are going our way, or when "good" things are happening in our lives.

How do you feel grateful during disappointment, frustration, anxiety and sadness, and when things aren't going your way?  I mean in mere seconds after the disappointment. 

I can (in retrospect) be grateful after the fact - say a day later, or a week later or a month later or sometimes even years later.  But what I'd like is to feel the unhappy feeling - the disappointment, etc., whatever - and immediately afterward, feel gratitude.

Any thoughts?