system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it so difficult to make things look random?

If you take, for example, a handful of pennies and throw them in to a corner, they'll be scattered randomly. But if you were to take these pennies and place them one at a time, it would look artificial, even if you tried desperately hard to make them look random. This may be a bad example, but the point remains the same. It may just be me, but I've always found it almost impossible to make something look like it happened naturally.
gpt
It is because of a phenomenon called "Poisson Clumping" or "Poisson Bursts." This phenomenon is that is random processes often produce clumps of events. In your penny example- if you throw a bunch of pennies on the ground, the Poisson distribution will describe how they land, and for large numbers of pennies, you will expect to get "clumps" or "large groups" of pennies. You won't know beforehand where these clumps will occur, but you can expect them. 

The problem is, while this is truly random- when we are trying to artificially make random distributions, we tend to avoid making groups. 

Two interesting occurance of this in real life. iTunes and WW2. First, iTunes. People complained that the iTunes random shuffle was bad, because occasionally the same songs would get played in clumps- but it turned out it happened just as much as statistics predicted it would. So iTunes was changed so that it was actually less random, to avoid Poisson Clumping. 

In WW2 the Germans were bombing Britain. The bomb landing locations were really pretty random, but due to Poisson Grouping the bomb landed in some clumps- which led the British to think that the Germans actually had better targeting ability than they actually did.