Every application has to deal with capacities and limits. If they didn't, they'd break.
Say your app just stores a couple hundred megabytes every second, because you imagine there's no such thing as a storage limit. Let's imagine disk storage could be expanded fast enough to support this and costs zero money. We still live in a universe bound by physics, and storage only goes so fast: you will eventually have too much data to process.
We can't assume CPU or RAM capacity is limitless. If your app is cracking crypto passwords, depending on the password and method, all of AWS's collective compute cycles still might not be enough to crack one password in a reasonable amount of time. Ask the people trying to make flight price comparison engines about resource starvation.
It's not even difficult to learn how servers work and affect your application. There's really no point to this crap.