Space is big, everyone.
But like, really.
Really, really big.
If you don't get exactly how hugely, undeniably, WE-DON'T-HAVE-THIS-WORD-LY big space is... I can't help you.
"The odds of hitting one of Jupiter's moons [with a laser fired randomly from Earth's surface], for example, are on the order of one in a trillion."
Of course, we land stuff on other planets (okay, cool).
We also get things into orbit around other planets
Not only that, but we get things in orbit around comets
Granted, if you haven't played Kerbal Space Program, you might not understand why the second is way more impressive
and the third is a multi-decade journey to land a grain of sand on a Tiger Woods hole-in-one he hasn't even tried to hit when you threw the grain of sand in the first place
Okay, I haven't actually done the math on the last one. But here's Rosetta's flight plan: Rosetta's Twelve-Year Journey to Land on a Comet | ESA Space Science HD Video
Now, tell me that your brain would have been fried long before the "second Earth gravity assist" and that by the time they got so confident in the trajectory that they just let it power off for two and a half years
you were pretty sure that the ESA is powered by Hogwarts.
Space is big, everyone. But we've got a pretty good handle on how big. At least, locally.
And by "we" I mean people who actually work on that stuff.
You have no idea how big space is. It's conceptually beyond you. Me, too, but we can at least find refuge in grasping the magnitude of our ignorance.