@Bad Alias
The one certain thing that is true about wizard towers is that the wizard is always alone.
When I was researching wizard's towers, best I could tell is that they are a pretty recent fantasy trope. I wouldn't go so far as always, but one of the main points of a wizard's tower is isolation. The wizard is usually alone. Most of the time when the wizard isn't alone, the company is more familiar than companion. Think Bob and house elves from Harry Potter as examples of this kind of example. Sometimes it's the apprentice. Sometimes it's one or a few regular old human servants.
I see what your saying and think that may well have been Jim's intention. Harry's slightest of actions can have far reaching consequences. Harry dwells on this often. I think the best example of negative consequences is from
White Night when Harry trashes the garbage can and Murphy drags Harry through the obvious consequences of his actions. They aren't the most severe consequences, but I do think they're illustrative of the point. The point is even reinforced when Harry throws Murphy's past behavior in her face. Even the comparatively little power she has must be used carefully. The best example of positive consequences is from
The Warrior short story.
But I think the things Harry points to and feels the most guilty over (at least some of them) are the worst examples of this. The reason I think this is because I ask what specifically could Harry have done differently that would have changed things for the better and what would likely happen if he didn't act at all? In the examples Harry provides, it's usually not much and something worse.
Wizard's "are [supposed to be] subtle and quick to anger," whereas Harry is just quick to anger. Perhaps if Harry had been subtle or had not been quick to anger, he would have had come to better results with Kim. I can see that. But given Harry's age and history, that wasn't ever going to happen. There's a reason the White Council is a gerontocracy. There's a reason the don't have much respect for a wizard who isn't already a century old (at least).
My views of responsibility for ones actions are probably best described by the legal concepts of foreseeablity and causation. Were the results reasonably foreseeable? Did the actions actually cause the foreseen result? Was it the proximate cause, i.e., were the two so factually remote that responsibility shouldn't fall on the actor. Additionally an intervening cause can severe the responsibility. This is the idea that one is responsible for his own actions (unless his will is so overridden by the acts of another that he didn't really have any or much choice left). [Person Harry knew] made a choice. [That person] had enough information to act at least safely, if not wisely. The person does not act safely, and sometimes outright foolishly, and comes to great harm. Harry blames himself, but it's person's choice that led to the results, not Harry's.
It's like teaching a child to swim to avoid the danger of drowning. A foreseen consequence is that the child will be comfortable with water and may swim without proper supervision and drown. Does that possible risk make a parent teaching their child to swim negligent? Note we could substitute any number of things here that parents commonly teach their children that avoid corresponding costs and have corresponding risks. Cooking, transporting themselves, gun safety, bathing, the birds and the bees, reading, etc.
But what about responsibility for not acting? Does Harry have any responsibility to act in the world? Or is it his responsibility to bury his talents in the desert?
