Well I can give you one example: the spider gene. Sometimes if a snake has the spider gene they get a "head wobble". This doesn't really hurt them, and they can be completely happy and healthy, it just makes their movements a little odd, sideways (sometimes), and well, wobbly!

as for other morphs? I'm not sure, but there is probably some other examples the more experienced hobbyists/breeders on here can give you.