the kicker
Remember that "defense of self or others" is a DEFENSE to a charge of manslaughter or murder. One might prefer not to be in a position to be tried for a crime at all, even if one has a really good defense (assuming the jury will buy it). But the kicker is the immediacy of the threat. An "emergency" (used as a technical legal term) is "an immediate threat to life, limb, or property". If there's no emergency, you don't need to pull your gun out. If you do so just to intimidate someone, you can be charged with anything from brandishing a firearm to assault with a deadly weapon. ("Assault" means an unpriviliged, unjustified, and unexcused offer or attempt to touch the person of another in an offensive manner. It does not require contact.) You pull out your gun, and the cop who sees you do it will be justified in shooting you.
On the other hand, "emergency" does not require the presence of a firearm. Just keep in mind the principle that twelve of your good, loyal, honest, and true neighbors are going to decide whether what you did was reasonable under the circumstances, or whether you should spend the next twenty years eating bologna sandwiches for lunch at state expense.