Why I don't want to go to a family gathering.

There's a bank holiday on next week for three days from Tuesday to Friday, and since the next day is Saturday, in actuality most people get five days off.
My maternal grandmother wants to see me at a family meeting during that period, but I don't feel like going to the gathering. My aunt on my maternal side gets on my nerves by talking straightforwardly to me like I'm an idiot, but my aunt-in-law, who is married to my uncle, tries to indirectly snub me. They seem to take their sons' or daughters' achievements' as theirs, or think having a nice spouse means they are also nice, which I disagree with. They are different individuals. They obviously are curious about my dad's whereabouts so they can gossip about it, which makes me sick. My mom is a snob, and so are they. I feel uncomfortable in the family gathering if my mom snubs others, then as a revenge I guess, they snubs me. At least, I didn't do any harm to them.