There are some bad decisions in life: substance abuse, unprotected sex, bad tattoos. The last item happens due to a poor idea, or poor craftsmanship. Now, the latter one usually happens when the person wanting to get a tattoo also wants to spend as little as possible, resulting in the business being taken to a mediocre artist, or to a plain amateur. Usually, the result is remorse, and the said tattoo being taken to be corrected, usually behind a cover up.
Now, there are people who do not learn from their mistakes. Scroll down to see sixteen examples.