Scripts make your game run smoother and faster, right?

What's the difference between changing properties manually, or scripting? Or scripting instead of manually changing properties.

I'm not sure what you mean by that but if a script lags or not is dependent by its efficiency.

Most of the time, even if the script is inefficient, it won't lag.

A script is something that allows the stillness of a game come to life. It can be used for almost anything you can imagine or want in a game-verse. They are used in MOST if not ALL popular games or popular games in the past. Scripts are a vital as GUI's.

How good a script is is determined by its efficiency only in my book.

Bad script:

script.Parent.TextTransparency = 0.1
wait(0.1)
script.Parent.TextTransparency = 0.2
wait(0.1)
script.Parent.TextTransparency = 0.3
wait(0.1)
script.Parent.TextTransparency = 0.4
wait(0.1)
script.Parent.TextTransparency = 0.5
wait(0.1)
script.Parent.TextTransparency = 0.6
wait(0.1)
script.Parent.TextTransparency = 0.7
wait(0.1)
script.Parent.TextTransparency = 0.8
wait(0.1)
script.Parent.TextTransparency = 0.9
wait(0.1)
script.Parent.TextTransparency = 1

Good Script:

for i = 0,1,.1 do
	script.Parent.Transparency = 1 - i
	wait(.1)
end

If you don't know how to script a good place to start is Youtube - Peasfactory and use the ROBLOX Wiki to relook up anything you forget because thats basically all I use it for XD.