Good for you! A bank is a "formal place of business" and as such, the tellers not only represent the institution, but should dress in a suitable way, which means BUSINESS ATTIRE; i.e. a suit and tie for men and something similar for women.
Cripes...I remember when bank employees, even those whom the public never saw/came in contact with, had a dress code, which most assuredly did NOT include a damned sweatshirt!
It was odd that I was just lazily scrolling and saw your post because this incident this morning really annoyed me.
I rememeber going into the city years ago-—hats,heels,and gloves.
I have one of those sidewalk sketches of myself,done in Manhattan in 1960,all dressed up for shopping,a dry martini,and lunch.
:-)