Your fear of snakes is likely older than humanity itself, so even if you can have rational control of yourself around a snake in real life they could terrorize your dreams. Snakes used to be a real and present danger in our environment for millions of years of our evolution. They are the unknown environment, the cunning adversary, the unforeseen consequence of carelessness.

In a similar way, you might find that you can manage to present yourself in social situations, there is a very human fear of being found out, cast out, laughed at, and/or rejected socially, since we are social creatures. Even nudists have dreams of finding themselves naked in front of their peers. If you spend your day putting on a facade of some sort, which you probably do if you have a job, then somewhere there is a part of you that you don’t want others to see, and in your dream they all see it big time and you have to deal with it.