It's pretty simple: don't be a murderous angry jerk.

If you reach the point where you're going to threaten people, or kill them, or kill _the entire party,_ the simple way to do that is... not do it. If you feel you _must_ do it, you're probably falling victim to [My Guy Syndrome], where you think "well, my guy would do it" as if it _remotely_ limits your choices about what he can do. You always have choices to act differently for the fun of the table.

You should probably go through a read of [Making Tough Decisions], which among other things talks at length about how to have your character get along with the party, have a reason to adventure with them, and generally not be disruptive and make things un-fun for everyone including yourself. This is especially relevant here. As a choice quote:

> When you think about a situation, ask yourself, "Is this the only way my character can react to this?" Chances are, the answer is, "No." Try to refine your character so that you can deal with situations that conflict with your alignment/ethos without resorting to ultimatums, threats, etc. This will often mean thinking in terms of compromise and concession to your fellow players, or at the very least an agreement to disagree. 

As that suggests, this might require transitioning your druid character into someone who _doesn't_ have a hair trigger before becoming a murderous jerk.

So, bottom line: read [Making Tough Decisions] and take its lessons to heart, and don't fall victim to My Guy Syndrome.

[my guy syndrome]: http://rpg.stackexchange.com/q/37103/1204
[Making Tough Decisions]: http://www.giantitp.com/articles/tll307KmEm4H9k6efFP.html