You want a scary story? Here is a scary story:
Once upon a time, nearly 10 versions back by now, add-ons didn't need folders. This wasn't a *terrible* thing, but the models tended to spam and clutter. Once in a while, someone would have an add-on installed wrong, and then you had to download add-ons/add-ons/add-ons/add-ons/somereallybigmodelyoualreadyhad.dts. Now, this next part is scary. In fact, it is so scary that you may want to just stop reading right now. You're not? Okay then...
Sometime, when joining a particularily noobish server...
Or maybe a malicious server...
Either way, sometimes...
You would...
Be downloading...
Add-ons...
And suddenly...
You were...
Downloading...
A music file.
Now, that is nothing odd. However...
The name of the music was...
add-ons/something/something/defaultmusicname.ogg!
So what, you ask?
Well, because it was the same name as a default music, the next time you hosted a server, it would be enabled, too!
So these ghosts of malice and noobism would haunt the servers, spreading uncontrolled, viral in nature.
And then, happy ending, Badspot released a new version that forced add-ons to be inside folders or .zip files with specific names, and all of those old problems disappeared!
Now for a second, much shorter, story:
In the first days of the original trench TDM, you did not dig 2x2 cubes, nor even 1x1 blocks. You dug 1x1 plates! Any you could only carry 12 of them!
If you don't think that is scary, just think of the lag caused by the spam from it!