Anyone can appreciate a tradition like yum cha (otherwise known as going to dim sum), but understanding what's what when it comes to the individual items is another thing entirely. Between the sheer number of dumplings, buns, pastries, and noodles, and the breakneck speed of the servers hawking them, option paralysis is almost inevitable.
So here's my not-at-all subjective, totally iron-clad ranking of the items you're most likely to encounter, so your experience is a little more informed. (Note that their names, whether in English, Cantonese, or Mandarin, can vary widely; I provided transliterations only where common enough stateside to be useful.)
24. Crystal shrimp dumplings (har gow)
Remember the kids who ate pencil erasers in grade school? Pretty sure they grew up to be the people who insist these dead ringers for already-chewed gum wads are the crown jewels of the dim sum canon.