A good thesis must include several components. A good format for this is,"Subject of essay is belief of subject because paragraph one subject/detail, paragraph 2 subject/detail, and paragraph 3 subject/detail. Here are a few examples of acceptable thesis's.
Smoking is unacceptable because it's unhealthy, it's an annoyance, and it's deadly.
Hate crimes should be stopped because their an embarrassment, they are unnecessary, and race should not matter.
Dancing is a good activity because it burns calories, it's fun, and it's a way to express yourself.
Good luck! Hope I helped!