Sometimes people like to add in details for character design. Sometimes I like to add in details for narrative effect. However, these details don’t always mix, and that’s a peculiar problem for tabletop gaming.
From the player perspective, the character created is simply the character created. How those nuances like, a physical impairment, drug addition, or a unique back story can impact the game are as varied as there are shapes for snowflakes. Essentially, there’s no one way this stuff will manifest. What about when the specific traits start to takeover the game? I’ve seen this happen, but the player doesn’t necessarily want to change their character. For example, once i had a player at a table whose player was a kleptomaniac. The problems were obvious. In another game the character was clean to the point of being obsessive compulsive. These are traits that can be troublesome.
From the GM perspective, these kinds of details worthwhile only insofar as they have a reason to exist. If it helps the game or story somehow then it has a place in the game. When the details belong to an NPC, it can be easy to remove an NPC its a problem, but the same doesn’t hold true for the players. The PCs remain, and this is where tension comes in.
I love well-crafted characters, but sometimes they most compelling aspects of a character are an issue in a game. This perhaps the kind of thing that helps illustrate the difference between a fantasy novel, and a fantasy role-playing game. The hard part is that there is no easy fix. Killing off the player’s character just because you think their persona is an issue for adventure is a bit over-the-top. You really do need to be careful about judging someone’s fun as being wrong. That being said, sometimes it can be too much, even if its within the rules, and its possible a compromise might need to be found.