Kid's Birthday Parties: Why do we do it to ourselves?

Why do we put ourselves through it?

We are going to attempt to put on a 5th birthday party for our eldest this weekend.

I say attempt because it is a Teddy Bears Picnic party.

Will it rain?  Will it be windy?  Will I be able to get my party face on in time?

The cake, the party games, the food, the weather, the stress!! 

Why am I stressed though?  All I really have to do is put on a picnic for 10 (yes count them) children between the ages of 5 and 3.  

I can't even decide on what type of food a to prepare, or which games to play and when in the hell am I going to get time to make the cake?

Frankly I'm getting a little freaked-out.