Yeah, I was just wondering...
How to make a 'light' not so bright, I use a prop_dynamic light-source but when I put the light there the whole area glows up, and it looks seriously unrealistic... How do I make it less brighter?

The fourth number in the brightness field. Also: https://developer.valvesoftware.com/wiki/Main_Page

You can also stick with the default instances, they have a really good light setting!

First of all:

Second... you can change each light entity settings including colour to make the lights less brighter. Which and how many lighting entities are you using in that area?