Ask HN: Anyone else pretend to get a phone call to escape awkward moments?
No synthesized answer yet. Check the discussion below.
That said, please build up some self-confidence, and have some really good reasons to break out of chit-chat, like "I'm late for a zoom meeting" or "Shit, I left my keys in the car". People say, rightly so, that "it's not about you".
In my fly-tying days, I'd feel weird about going to a sewing store. Heck, they had all kinds of yarn, burlap and scissors ideal for fly-tying. I got over the feeling, because "nobody really cares".
Besides, a little notebook or block of postit-notes looks smart. "I have to write down this idea before it goes away forever" and that's so often the truth.
Building self-confidence (or just a don't give a shit attitude) prevents the social anxiety, so you don't have to solve it.
The office gag wasn't social. It was just fatigue. I guess there always were and will be situations where we need an exit. FWIW, I am retired and living alone in the boondocks, and have too few interactions, so consider the value of just being in the people world. I plan to move, to be closer to family and friends. Most are over 50 miles away. I might run into one of those hasty exits. Right now, my excuse would be "I have a long drive (I do) and want to get home before dark"
Of course, I've had many years to make excuses, most of which were/are valid. Oops, I've got to go to the pharmacy/hardware store before it closes!
Good luck.