What is the halacha regarding dancing/standing on a table?
I see there are communities that do it at weddings and Hasidic places
It is commonly said that a person should not stand on a table because “shulchan domeh l’mizbeyach”. The source for this however is not very clear. There is a halacha (Rema Y:D 282-7) that we may not sit or stand on a bench or chair that has seforim on it, but when there aren’t seforim on it, it seems alright. There are indeed poskim that discourage it, and some say not to, however, as you write, it is the custom is some communities that they do stand on a table by “tish” or for other reasons.
See Yosef Ometz 64 brings from Sefer Chasidim (920) not to stand even on a table that one eats. However when looking at he Sefer Chasidim inside it appears that it is specifically because it was a table meant for seforim, (even though he also used to eat there).
See Rivivos Efrayim 6-95 writes not to stand on a table, Gam Ani Odecha (Shas Vinyonim Shonim) 86-64 in the name of R’ C. Kanievsky shlit”a, that according to kabbalah it is proper not to, (not that it is forbidden).