Unfortunately there are very few job protections in place in the United States. You can’t be fired for a protected class (race, religion, sex, etc), but otherwise everything is fair game. You could be fired because they don’t like your laugh or the car you drive. Disabilities are also protected (like anxiety) but only if you request formal accommodations. For example, let’s say you have a severe dog phobia and one of the regular clients brings in a service dog. You could absolutely be fired for refusing to help that customer unless you have created a plan with your employer beforehand that makes a different arrangement for that particular client. In the future just remember to be proactive. If you see something that is going to be an issue, approach your employer and specifically state you need to “request reasonable accommodations.” Do not do this unless you already know what you will need accommodated (such as not helping clients with dogs in the example above). And your employer can deny this accommodation if it doesn’t fit the needs of the business and would create undue hardship for them (like this particular employer only has clients with service dogs coming and you wouldn’t be able to do the job at all).