Long shiny black coats that Chassidim wear on Shabbos and holidays and for other formal gatherings such as family weddings. They look uncomfortable as hell but in actuality they are so super awesome we frankly feel bad for the Litvishe and sometimes stop making fun of them for up to three minutes at a time.

Consider: when wearing a suit, you must, perforce, wear uncomfortable pants. When wearing a Bekishe (or Chalat'l, or Tish Bekishe), you can wear what pants you like. What, you thought the checkered britches and white tights were a fashion statement?