The Agony of Writing A Query Letter

I've been agonizing over this for the last few WEEKS. I have several different variations on my query letter, but can't seem to make up my mind over which one works best. I've asked for some feedback, but at the end of the day, the decision is in my hands. I thought that writing my manuscript was going to be the hardest part. I love my story, I love my characters, I love writing, but why does so much have to ride on a query letter??? It's frustrating, and I'm sure all you other writers can relate. I've done my research and have found several agents that might be intersted in my story, and each has a different set of criteria for query letters. Oh well, at the end of the day you can't please everyone. As hard as it is to realize that, you need to in order to move on. Wish me luck!