You don't need an excuse or a reason. Just tell them you don't want to drink.

I'm not an alcoholic in the least and I don't drink at all. The shit is poison and I just don't like how it makes me feel physically or mentally.

I would probably skip the whole thing we're I in your shoes ...do you HAVE to go?

The moment you feel obligated to provide an excuse for something that is no one else's business is when you forget about who is the most important person in your life. That person is you. Your life. Your decisions. You don't owe anyone any explanation or excuses and anyone who suggests that you do is the one with a bigger problem than you.

you must work somewhere amazing if you don't have to get wasted to put up with your coworkers at the Christmas party.

So much pressure gets put on people to drink. Drinkers have no idea. And there are so so many reasons for people not drinking that you should never force them to disclose, never never. When you ask someone why they don't want a drink, you might think it's a simple question, but you might actually be asking them about abuse, terminal illness, addiction, family tragedy, etc etc. If you offer a drink and someone declines, the ONLY thing we should be doing is offering a nonalcoholic beverage and moving on.

Some hate to drink alone, it causes personal reflection.

those "virgin caesar s" or other cocktails look like the real thing so nobody knows the difference and you don't have to talk about it. Put in lots of ice with mix and it looks like a drink. This is just to avoid the discussion. But I agree that it isn't anybody's business and I'm proud of you.