1. They are loud and obnoxious.
2. They do nothing that can't be done with a rake or even a good pair of hands, and therefore contribute to the growing obesity problem in this country.
3. Even if you use them, you still end up having to use a rake or a good set of hands to bag the leaves anyway.
4. Did I mention the part about them being obnoxiously loud?
5. They require either gas or electricity to run, so they are bad for the environment.
6. They are un-neighborly: Aside from the obnoxiously loud noise, they are also frequently used to blow leaves out of one yard and into the next in a pass-the-buck fashion.
7. They inhibit napping, which I firmly believe could be the key to world peace.
8. They require the user to look this ridiculous:9. See the ear muffs above? Those are not provided for innocent bystanders who may be trying to nap. Obnoxiously loud!