I daven in a shul where the gabbai is a old guy and I have 5 names so when he calls me to the torah he always messes up, and it disturbs the minyan. Can I just tell him the 2 names that he and all the people call me by?
It is the common custom, among many communities, to people up by their full names. There is no obligation, however, to do this, and if it disturbs the congregation you can tell the gabbai to use two names alone.
Note that this can have halachic ramifications concerning you “halachic” name (concerning gittin), if the other names will be entirely forgotten.
I hope that your father does not have many names!