Even if time doesn't literally flow from past to future, it still seems that the world is strongly lopsided in time. If you take a movie of a typical everyday scene and run it in reverse, everybody laughs. They have no trouble spotting the deception. In real life, raindrops don't rise into the sky and broken eggs don't mend themselves. A vertical stack of still frames would display a structural directionality.
People grow old, cars rust, eggs break, snowmen melt, radio waves spread out from transmitters.
It can be misinterpreted though, because arrows also fly, and so the term could also refer to time flowing. The correct way to picture the arrow of time is by analogy with a compass needle or weather vane, which point in a direction but do not move towards it. Well, most irreversible processes are examples of the second law of thermodynamics. This says that in an isolated system heat will flow from hot to cold, never the other way. The end result is a state called thermodynamic equilibrium, with the heat distributed evenly at a uniform temperature.