I went to a short notice Murder Mystery party last weekend, and was reminded of an important aspect of gaming.
Lots of games get much better if people can involve themselves more fully in the roles they are endeavouring to portray. Murder Mysteries are a great example of this, the core skeleton of the game is weak, a lot of the enjoyment and entertainment is found from taking your roles and filling them out into fully fleshed out characters.
It’s important to understand when it’s appropriate to play a role. Chess or other abstract games are not well suited, roleplaying games are obviously ideal.
If you are designing a game, look at the options people have to play the role they are taking on, and consider ways that you might be able to enable players in this, maybe by layering a history and backstory onto a player’s character, even if it has no mechanical application, it might just make the game more fun.