For me, I view Apollo as the highschool quarterback winning the homecoming game.

In the context, its a great achievement. A lot of time, effort, and luck all came together at just the right moment to create an entertaining spectacle. The school is all happy and celebrating, students will remember that moment for years to come. But in the grand scheme of things, it's not that big of an achievement since everyone there will move on to bigger and greater things, except they won't have a student body cheering them on.

I think saying the Apollo program is one of the greatest achievements of mankind falsely puts it on a pedestal and forever sets up all other achievements as being lesser. Makes us all feel like anything that isn't chasing that glory isn't worth it. It's an achievement for sure, but not the biggest. If I had to give the greatest achievement in space technology to anything, I'd give it to either GPS or GOES.