引用自 yes：

How'd that torch not set fire to the couch?

引用自 McJeb :I：

It is either a fire-retardant couch, or 'tis a magic couch that is blessed or cursed by a force or entity. [/qoute]

引用自 Alex_D_Vasilkov：

> throwing molotovs all day
> no damage to surroundings
> no questions asked

Bunch of ♥♥♥♥ing geniuses is what you are.

Why thank you Alex, I am a genius. I was once a simpleton, but now I am a super-genius. I was granted my vast intellect and wisdom by a force from a higher plane of existence far beyond our mere mortal comprehension, even I do not know why I was given this gift.
With my gift, I created masterpieces such as a highly accurate high-quality Angel Dust NPC for Garry's Mod.
Upon looking at this work, you can tell I am gifted. I wish to share my knowledge and wisdom with the world, which is why I made a guide on how to make a Gucci mask in Payday 2. As you can once again see, I am gifted greatly. I have again attempted to share my wisdom when I stated that "It is either a fire-retardant couch, or 'tis a magic couch that is blessed or cursed by a force or entity" in response to the question of "How'd that torch not set fire to the couch?". I hope I have blessed you all with great knowledge.
However, I am not yet done. It is possible that the couch and all of the surroundings are fire-retardant, or it is also possible that the fire in Left 4 Dead 2 is harmless to everything except people (such as the survivors and the infected). Hence, the fire in the game is magic fire and the world of Left 4 Dead 2 is a world of magic, which explains several magical items on the workshop. Since the world is of magic, several characters have magic roots. The character of Bill is most likely a secret wizard (hence the white beard) or Papa Smurf who was turned into a human, the witch is a mythological creature such as a siren or the Wendigo, and Francis is a biker who once worked for a shipping company called Porsche. Ellis is a being from a higher plane of existence far beyond our mere mortal comprehension, now stripped of his power, Nick is a gambling con man, and Rochelle delivered pizza and not news. Coach was once a football coach, the most modern type of wizard, and the Midnight Riders were the Knights of the Round Table.
Hopefully I have uncovered the secret lore of Left 4 Dead, you are very welcome. I am open to all of your opinions and suggestions.