I always attended company holiday luncheons, dinners, parties, whatever.
My advice........
eat, drink, and be Mary if that is your thing, the party is for YOU, appreciate it.
So many wish they had a job, to gripe about the holiday party!
My technique if a buffet......
elbow your way to the front of the line, load your plate with all the good stuff,
place plate on table with your awful co-workers, go to the dessert table, load up with all the good stuff, go back to table and leave dessert plate, go back and fill another plate for a "invalid" relative that lives with you (your dog Ruff loves smoked ham, right?)
return to table and eat like John Belushi on Animal House.
Stay long enough to annoy everyone at your table with bad manners (some need no coaching) and then leave with enough food to feed Ruff and your girlfriend (does she like smoked ham?)
Next year, you will have a table of your own!