The Earth Is Round: No, you can' fall off the edge. There was a time when people thought the earth was flat, in fact, there is a group of people that STILL believe the earth is flat. Weirdos!
Classical Elements: Pre-socratic philosophers like (Thales of Miletus, Anaximander, Anaximendes, Heraclitus, Paraenides etc.) postulated that the world was comprised of four classical elements: earth, fire, water and air. It was the first time that man tried to explain the world without relying on mythological explanations.
AAAAND then we discovered that there are ACTUALLY 114 elements known to earth, starting with Helium.
Germ Theory: just simply by eliminating the thought that "bad air" makes you sick revolutionized the globe. Bacteria makes you sick. Use soap.
Computers: Who can imagine life with out computers now, in the 21st century. Remember having to do everything by hand? And may the gods forbid that you actually get your entertainment via magazines and newspapers. The internet is much more efficient.
The Number zero: everything from quantum physics to binary code relies on this mathematical principal.
Women's rights: Women deserve the same treatment as men? What an interesting idea! It wasn't until 100 years ago that women gained rights.
Fast Food: Now you don't have to wait 2hrs for your meal to be ready! Making you more able to put in more hours at the office.
Vaccines: Smallpox, polio, measles, mumps --- they were all diseases that were virtually incurable. It wasn't until vaccines entered society that people started to live longer and in higher quantities.