D&D players of Reddit, what is your best "house rule" and implications has it had on one of your games?

1. In tight situations you have 3 - 5 seconds to react, which usually leads in interesting and hilarious results. An assassin was wounded and dying, there was little time to question him and after DM started counting down the player paniced and just yelled "what's your name?!" In which the assassin replied with "John" followed with an "URGH" upon dying, leaving us completely clueless.
   — Antikristus


2. In combat, describe your attack before you roll. So they do, and I tell them how it works out based on their roll. This often leaves arrows sticking out of necks of massive creatures, broken arms, shattered knees, etc. Not only does it give the fight more flavour, but it allows for a more creative fight. The next attack might target that arrow in the neck, the creatire might have disadvantage after you broke its arm. I had one player once describe stabbing their rapier through the foot of a giant and into the floor. This hobbled the giant, he didn't want to move, and didn't want to fight, so he sat down and the players talked it out with him.
   — generic_brand_cola


3. I feel like this isn't uncommon, but the Rule of Cool basically means if we do something awesome, even if we might not technically be able to according to the written rules, our DM might allow it.
   — bluest_bird






4. My players don't like the concentration damage rules (roll every time you take any), they find it tedious and annoying and not fun. So, I gave them the option to ignore those rules. They agreed. Now all enemy spellcasters don't need to worry about concentration unless stunned or whatever - so many casts of Haste, Fly, Globe of Invulnerability etc. going off without a hitch. I'm feeling that they are beginning to regret their decision.
   — Auesis


5. players were issued Oreos in lieu of gold coins, and had the choice of either eat them, loan them or use them in game for purchases (in which case, me, the DM would eat them or hoard them). Lets just say they became VERY reasonable about purchases, and started taking in game economics seriously/
   — Freevoulous


6. My party started this during the days of threats/comfirms for critical hits in 3.5 and have kept with it ever since. Basically we decided that if you had to roll to confirm a crit, one could also roll for a “botch.” So the way it works is that if you roll a one, you roll again and if you get another one you’ve confirmed your botch. Then you roll a D6 to see what happens. 1-5 are pretty mundane (e.g. fall prone, throw your weapon), but 6 is a magical mishap. Our DM wrote up 100 separate possible mishaps, and you roll the percentile dice to see what you get. As you can imagine it’s pretty rare, but people have been turned permanently purple, had their gender changed, been transported to a different plane, etc. It’s added a fun, random element to the game and made a bad roll interesting. EDIT: Clarity.
   — Fencius






7. +3 for any rolls made while naked.
   — coinbaseisslow


8. I have two: 1. The intimidation skill is now Strength basted. I think the 400lbs Orc warrior with arms the size of tree trunks should be able to intimidate the 90lbs Bard. Not the other way around. 2. The Vicious Mockery spell's success chance is dependent on how good your mockery/insult it. This really adds to the RP of the game, and its extremely entertaining.
   — nagol93


9. Talking is a free action. Look, I know it takes time to have a conversation in real life, but it's way more fun to be able to taunt someone over several lines during a battle or have a cool cutscene-like dialogue in the middle of a terrifying plot. It just makes things better. Let your players talk. Also, if you roll a 1 or a 20, no matter how boring the check you're making, I will give you something neat of the appropriate good/bad flavor.
   — Alcoraiden






10. I give players advantages for descriptions and acting that are evocative, realistic, creative or any combination of the three. (This is actually in 5e as "inspiration" for various other uses) Which has led to the party's army officer character having her whole line of tactical thinking explained, the party goofball bard describing the increasingly absurd and unlikely ways he hurls knives, and so on. It's great fun
    — Reworked


11. We did a 'boss mode' for a limited time, when we were talking to a bbeg. The idea is that for the encounter, there isn't 'table talk,' everything the DM hears, the NPC hears. Any discussion of tactics etc. Obviously we need to ask DM questions out of character here n there but only when essential. It wouldn't work all the time, but for a limited time in a special encounter it was very entertaining and tense. The talk obviously deteriorated into a fight, but we didn't get to plan like often happens and we didn't know if all our group was on board for it because we couldn't tip our hand by asking them in front of the bbeg.
    — YouAreUglyAF