I never let my characters have a skill called "horsemanship", "swimming" or "first aid". Know why? Killing a player because they don't have these skills is painful. Boring. Nothing is worse than being in bored and in pain. I wrote a book just for that reason.
If a player wants to role play that they can't ride a horse, the other players can cart him around like a bag of oats. No need for silly rolls. I'm not prepping a campaign for players where one of them wants to die of a horseshoe to the face.
How hard it is it to jump in the ocean in a full set of plate armor, shield and sword? Super easy. Why roll? It's obvious as to what happens next.
One time, I amused myself with this very scenario by having the player to roll a four to succeed. As an epic battle of life and death raged around him, he was the only person not in on the joke.
"No... you're still aliv- er, hanging in there... keep rolling..."
I have this rule that characters aren't dead until they hit -10 hp and once you hit zero or less, you lose one point per round. Anyone attending to that character stops to the hit point drop. It creates an interesting scenario where the wizard drops to -4 hp, and all the way down to -7 before the cleric hits him with a cure light wounds for 4 points leaving them at -3 until they heal naturally. It's a couple of days before the wizard wakes up.
No need to screw any of the characters by telling them the medic couldn't figure out the arrow was the problem due to a bad roll. This is realistic for some reasons and total BS for others. In the Middle Ages, if you didn't respond to treatment, they'd bleed you. Save vs. Barber? No thanks.
Why do this? Because I like to reuse bad guys. A dude with a club isn't assured of killing someone with it unless they beat that person downed and beyond. If THAT doesn't occur to the players, well, I can be lazy with their enemies and they can have endless rematches with opponents. My NPCs can have names.
Which is more legendary, beating someone to death in a dark, dank, dungeon or having a horde of people who refuse to fight you because they don't want to be whupped again, third time this month?
In my last aborted campaign, the "heroes" hacked apart 4 raiders that wouldn't surrender and took two captive. The captives were obviously intimidated by the PC's bloodthirsty treatment of their friends. Although the campaign ended, one of the players put two and two together and realized that the prisoners were the ones responsible for most... actually all of the raiding parties kills in the village. The 4 guys killed were a patrol that didn't mix it up with anyone. They let the wrong people live.
Trust me, that would have come back to haunt the party.
The lesson is, don't give people stupid skills.
