D&D 5E Rules We Have Been Doing Wrong This Whole Time

[Reynard]

Pretty reasonable. Otherwise, you could do negative damage (such as with an attack that gets -2 as a modifier) and heal the target as you hit them.

Step 1: Roll 3 strength
Step 2: Punch people.
Step 3: profit (hp).

 

[Maialideth]

The description is ambiguous.

It is not stated in the description of Magic Missiles, but in the section for Damage Rolls on page 196 in the PHB.
"If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them". I believe it was Sage Advice that clarified it.

 

[J.Quondam]

Wait... knock makes a noise? Really?

 

[Seramus]

Some people run Perception "wrong", allowing you to use it when you are distracted with other tasks.
Some people don't use Marching Order or Other Activities, just improvising as they go.
Some people run Darkvision "wrong", imposing no penalty to perception in darkness.
Some people let a Nat 20 always succeed even outside of combat.
Some people let you Long Rest whenever you have the time.
Some people forget V is mystic words, and S is forceful or intricate gesticulation.

 

[billd91]

It is not stated in the description of Magic Missiles, but in the section for Damage Rolls on page 196 in the PHB.
"If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them". I believe it was Sage Advice that clarified it.

It is a weird justification that JC used, particularly since you can hit a single target with all of the missiles and the rule on 196 doesn't directly address that at all.

 

[Reynard]

It is not stated in the description of Magic Missiles, but in the section for Damage Rolls on page 196 in the PHB.
"If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them". I believe it was Sage Advice that clarified it.

Specific beats general, though, and the spell description can easily be read as "roll 1d4+1 per missile."

 

[Reynard]

Some people run Perception "wrong", allowing them to use it in situations the book suggests they should not.
Some people don't use Marching Order or Other Activities, just improvising as they go.

These two aren't about "wrong" though, just preference.

Some people run Darkvision "wrong", imposing no penalty to perception in darkness.

This one happens A LOT.

Some people let a Nat 20 always succeed even outside of combat.

I don't know what that is even a thing. "I rolled a 20. I seduce the dragon!" ugh.

Some people let you Long Rest whenever you have the time.

This is again about preference and playstyle, not "not knowing the rule."

Some people forget V is mystic words, and S is forceful or intricate gesticulation.

This. Casting is NOT subtle.

 

[Seramus]

These two aren't about "wrong" though, just preference.

"Wrong" in the sense that the book says you can't use perception when you are distracted or doing certain tasks. Not "wrong" in the sense that the DM can do whatever they want as long as everyone is having fun.

This is again about preference and playstyle, not "not knowing the rule."

I mean the limit of one Long Rest per 24 hours.

 

[James Gasik]

I admit when I started playing, I got darkvision wrong as well, mostly because everyone else I was playing with did. Then I started running 5e, and my first adventure was Sunless Citadel, a tier 1 adventure with tons of DC 15 and 20 Perception checks. The players all had darkvision, and were planning to not use any light in the adventure.

On a whim, I looked up darkvision, realized how it worked, noted the disadvantage on Perception, and it didn't take long before someone started using dancing lights, much to the Rogue's annoyance.

 

[Reynard]

I mean the limit of one Long Rest per 24 hours.

Ah. I haven't made that mistake myself, maybe because it is a new mechanic so I had to actually read it?