Thin Cookies Are Bad Cookies
If you make a cookie too thin, it will break. This can happen before it's baked, after it's baked, or like whenever really. So don't desing a cookie cutter thats too thin. Or for that matter a cookie cutter that results in one side of the cookie being too heavy. Or a cookie cutter with a lip, because that makes bending it a terrible experience all around. Anyways, here's my buggy cookie graveyard (mass-grave?):