My 13 year old son has an autoimmune illness and he deals with frequent anxiety.
It is a constant battle for him to deal with his issues and he swears that chocolate cupcakes still warm out of the oven are a cure-all for a bad day.

This is what he writes:
How chocolate cake makes everything better

When you are feeling down or depressed and you need something to make you feel better – eat chocolate cake.  Cold, warm, hot, all of them are delicious.  Every bit of soft, spongy, rich chocolatey taste gives you the sensation where the taste is so good that you enter your own space.  It is like the world of stress doesn’t exist and all of your problems and worries are gone.  Afterwards you can focus on your work, your mission, your goal.
Life lesson: Eat Chocolate Cake!

I can’t argue with him even if I am not the world’s greatest chocolate cake lover.  But just spending a few minutes calmly enjoying something that you love is going to make a big difference.  Particularly if you are becoming overwhelmed by stress and anxiety.  You are seriously not going to get anything done while you are panicking.
Rather watch your manager’s expression while you sip your tea and eat your snack as they stare you down expecting your deadline to be met yesterday (don’t tell them I said this…)

So here is my son’s favourite chocolate cake recipe.  It sounds crazy but that is because it is called a crazy cake but trust me on this.  It is a fast and easy way to make cake.  You can make it into one large cake (enough to share with everyone in the office) or make 24 cupcakes – freeze them all and take one out each day to pop into your lunch box….

3 cups flour
2 cups white sugar (stop right here if you are diabetic or a health food fanatic)
1 teaspoon of salt
2 teaspoons baking powder
½  cup cocoa powder

Mix all of these ingredients into a large bowl and then make three wells and add:
¾ cup sunflower oil
2 tablespoons vinegar (really!)
2 teaspoons vanilla essence or extract (or be daring and use a different flavouring – I’m quite partial to caramel)
Put each one into a well (don’t worry if they overflow or the wells collapse.  It works anyway)
Top the whole mix with 2 cups of water and mix well until there are no lumps (I do this in a mixer but you can do it by hand)
Pour into a prepared cake tin (or in a foil roasting tin that you can just throw away when the cake has been eaten) or into 24 cupcake cases (put them in muffin tins because the mixture is really runny)

Bake at 180 C for about 40 minutes for a cake and 25 minutes for cupcakes