I find <PERSON>'s analogy somewhat confusing, so I'll propose a slightly different answer. The repulsive "force" that causes the expansion is significant on very large scales. Galaxies (also stars, planets and humans) have average density large enough to ignore it (or, to put it differently, they clump together faster than the expansion of Universe pulls them apart). If the Universe continues its accelerated expansion, galaxies, stars, planets and humans (if there are any at that point in time) will be eventually pulled apart as well.
I'd also like to provide a quote from the set of lectures "Quantum computing since Democritus" by <PERSON> (which I highly recommend). They are mostly dedicated to computational complexity, but in one of the last lectures he talks about cosmology:
So what is this cosmological constant? Basically, a kind of anti-gravity. It's something that causes two given points in spacetime to recede away from each other at an exponential rate. What's the obvious problem with that? As the <PERSON> character's mother told him, "Brooklyn is not expanding." If this expansion is such an important force in the universe, why doesn't it matter within our own planet or galaxy? Because on the scale that we live, there are other forces like gravity that are constantly counteracting the expansion. 764
Imagine two magnets on the surface of a slowly-expanding balloon: even though the balloon is expanding, the magnets still stick together. It's only on the scale of the entire universe that the cosmological constant is able to win over gravity.
You can talk about this in terms of the scale factor of the universe. Let's measure the time t since the beginning of the universe in the rest frame of the cosmic background radiation (the usual trick). How "big" is the universe as a function of $t$? Or to put it more carefully, given two test points, how has the distance between them changed as a function of time? The hypothesis behind inflation is that at the very beginning–at the Big Bang–there's this enormous exponential growth for a few <PERSON> times. Following that, you've got some expansion, but also have gravity trying to pull the universe together. It works out there that the scale factor increases as $t^{2/3}$. Ten billion years after the Big Bang, when life is first starting to form on Earth, the cosmological constant starts winning out over gravity. After this, it's just exponential all the way, like in the very beginning but not as fast. 764