I would say napping will somewhat improve my mood. In a situation like you described above (Kathy) I would say for me it would be because an argument or anything that can be stressful or cause anxiety is overwhelming, has my body in overload as well as my mind, its no wonder we're tired and need a rest.

I can also say that if I fight taking a nap (and I often do because I worry I won't sleep at night) then I am more irritable then ever. If I do lay down for a power nap (I try not to exceed an hour but a typical power nap seems to be between 20 to 30 minutes), I will feel much better when I wake up. Although, I can't say whatever it was that was bothering me before won't be waiting for me when I wake up - I'll just be more able to deal with it in a healthier way.

Its funny you post this because just the other day I was searching webMD on foods and things that will give me more energy during the day and power napping was listed and actually discussed how the rest from the power nap can improve one's mood and energy level.