I've grown accustomed to visiting the flash sushi train downstairs for lunch 2 or 3 times a week now. I didn't like using their disposable chopsticks, as it's needlessly wasteful.
Today I brought along my own pair for the first time (a handsome pair in a box which I bought when I lived in Japan). When I whipped them out there was giggly surprise from some of the staff. I think it's usually only nerds and fussy old people who carry their own. Younger/Cooler folks are expected to walk around with only small electronic devices and a wallet full of cash in their pockets.
One young woman working there said her parents bought her a pair last year, as there were stories in the news describing some of the nasty chemicals used in making the disposable kind. But she's too embarrassed to take them anywhere, so they sit unused at home, making her feel guilty.
All up, it was a good move. I got fussed over, with a pat on the shoulder from the owner, and another person there rushed to get me a bowl of my favourite Korean salad before I'd even asked.
So my advice re chopsticks is, fear not embarrassment, take your own.