I have to disagree with the idea that a player getting bored and stabbing the innkeeper is a sign of poor pacing. You're putting the blame for the player's action onto the DM! I would say that when this happens, it is often because a player is bored of not being the centre of attention; stereotypically, it happens when the Barbarian player - or Crab Bushi, or whatever - is wanting everyone to pay attention to them again, not to the Bard. For another example: rangers deserve the opportunity to roleplay being a protector of the wild with a low-stakes scene between them and some woodsmen in the forest, even if it isn't very exciting for the Wizard in the party. In short, one player does not get to say, "I don't want this scene any more" and take action that will negatively impact other people's enjoyment; the wizard who decides to just firebolt the woodsmen is at fault, not the DM for presenting that scene.
In addition, I'd push back against the suggestion that every scene must have real stakes. This is not a book, or a film, where we can craft everything to be self-reverential and important for revealing character; all we can do as DMs is present the scenes that suit the story and the characters and the location, and hope to let the players have fun in them. I'll happy have a scene of a player just speaking to a Dwarven smith and booking their platemail, even if there is no 'loss condition' available; that player can take the opportunity to roleplay regardless. Indeed, I'll occasionally try to have a 'low drama' session, where the party just exist in the world. They meet people, they make plans, they get into discussions about whether armour should be ornate or plain, they, in short, roleplay. I'll make sure to add a combat encounter - or at least the option for one - into such a session, but I think that this kind of session can be really good for letting the players enjoy their characters and the world, without the pressure of saving the universe or rolling initiative. Often these scenes can lead to interesting things later on, for example when the party takes a shine to a given NPC, or when your description of the injustice in Baldur's Gate gets their blood pumping.
As always, it probably comes down to a group mismatch. If the DM is wanting to have low tension scenes where the party exists in the world, and Bob the Barbarian keeps hitting the NPCs so he can get back to combat, then sooner or later the game is going to have to change - either to not have those scenes, or to not have Bob in it.