If you listen to commencement speakers without falling asleep, you will often here the same phrase "make a difference"
This has to be one of the worst bits of advice well-meaning commencement speakers habitually offer to the youth of America. This hackneyed mantra assumes that everything needs to be changed, when that's clearly a very bad idea if some things are working just fine, or have a low priority for change. Likewise, this advice assumes that all differences made are good changes. This is an extremely naive assertion. Making changes just to make changes without any rational thought is something a monkey can do, not what we expect out of college graduates. Change solely for change's sake can easily lead to the collapse of everything we value in society.
In a nutshell "hope and change" is terrible advice to give to graduates. A monkey can do this without prompting.
"Evaluate and improve the world" would be far, far better advice. This is what we should expect from a rational, critically-thinking responsible citizen.