I don't like a birthday fuss either, but don't mind a meal out or at my parent's summer home. I live about 35-40 mins from there, through the lovely mountains in our area, so it's no problem driving that distance. With sleep apnea, I don't want to do any long distance driving, as road watching can be sleep inducing in people who are perpetually tired.
I also can't get out of attending at least a few family functions when my parents are up here during the warm months, as they are renting me the trailer I live in. It's not a good idea to upset your landlords.
They know I am not a social butterfly, and won't attend every function, but would get too upset if I refused to attend ALL functions. Being NTs, they think there is something wrong with being a loner. If you are alone and miserable about it, then yes, there is something wrong, but some people like being alone. There is nothing wrong with liking being alone, but NTs just can't seem to grasp that anyone might actually like being alone, so my parents think there is something wrong with me over this--I mean besides my other problems. So I do try to do a few things with them when they are up here--just to keep my family social membership current--and to keep them from calling for the men in the white coats.
Don't stress too much over this. Just have a meal in or out with them, and pick occasional get-togethers to attend, but let 'em know you have other plans, when you really don't want to attend any other events.
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau