This is the example I use with my clients to explain why a single member LLC usually doesn't protect anything:

Assume you start a beer delivery service. You form an LLC and operate the business out of an LLC. One of your drivers runs a red light and hits a school bus and kills several children. The parents of the kids can either sue the negligent driver personally, or they can sue your LLC that the driver worked for. In this case your personal assets are protected by having the LLC in place because you were not personally involved in doing anything negligent or wrong.

However, if you are the guy driving the beer delivery truck, and you're the one who runs the red light, the parents still have the option of suing the driver (you) or your LLC. If they sue you, all of your personal assets are at risk in that lawsuit.

If you have an LLC, and you are doing most of the work for that LLC, the LLC itself doesn't provide much liability protection. This is because you are probably going to be personally liable for any harm that is caused.

At the end of the day, the best liability protection is good insurance.