That one screw....

[nitro2k01]

You all know that one screw I am talking about, the one that refuses to turn or it turns but refuses to leave its spot.

How do you get around this guy? Why is he always the last one too?

There's a logical explanation. When the thing was assembled, the two pieces of the casing we're squeezed tight to each other. This means that the pieces of the casing builds a pressure outwards. What this means to the screws is that they will sit tight because of the friction between the threads on the screws and the corresponding threads in the hole.
When all screws are in place, the pressure is divided between the screws. The more screws you unscrew, less screws share the same amount of pressure, which means there's more friction on every individual screw.

[Dr. KillGood]

You all know that one screw I am talking about, the one that refuses to turn or it turns but refuses to leave its spot.

How do you get around this guy? Why is he always the last one too?

There's a logical explanation. When the thing was assembled, the two pieces of the casing we're squeezed tight to each other. This means that the pieces of the casing builds a pressure outwards. What this means to the screws is that they will sit tight because of the friction between the threads on the screws and the corresponding threads in the hole.
When all screws are in place, the pressure is divided between the screws. The more screws you unscrew, less screws share the same amount of pressure, which means there's more friction on every individual screw.

What?

[nitro2k01]

What?

I was answering the question "Why is he always the last one too?". I know you asked that question almost like a joke, but there's a reason why the last screw can be harder to unscrew. I'm sorry if you didn't understand a word of what I said. :p

[Kurt_]

In simple terms: The case is only held on by that one joint, and if it's even a little out of whack it's going to push sideways on the screw making it harder to come out.

[Aguiluz]

In simple terms: The case is only held on by that one joint, and if it's even a little out of whack it's going to push sideways on the screw making it harder to come out.

So that's why it's hard?

[Bibin]

Solution: Hold the case together firmly while screwing?

[Electric Rain]

Solution: Hold <s>the case together</s> firmly while screwing

Wow, am I really 18? I don't think I ever matured past 13.

[Metroid fan]

I don't think that anyone ever does get past thirteen! (That was hilarious)