Weapons, including guns, are useful for protecting yourself and others around you. They don't usually become an issue until they are used improperly. You can face criminal charges if you are accused of using them in an unlawful manner.
One charge that is possible is assault with a deadly weapon. This charge doesn't even require that you actually harm someone with the weapon. Merely using the weapon to intimidate someone is enough to lead to criminal charges. You only have to put the person in fear of their safety for this charge to be levied against you.
Some people have a misunderstanding about what constitutes a deadly weapon. While guns are obviously included, it is possible that anything that can be used to cause serious injuries or death can fall under this classification. It might depend on how the object is being used. For example, a tire iron in your trunk isn't a weapon, but if you lift it up while threatening someone, it could be considered a deadly weapon as long as the person reasonably thinks you will strike them.
If you are facing charges that relate to you brandishing a weapon toward someone, you need to think carefully about how you will handle your defense. Not only do you have to show that you didn't intend for the weapon to come across as threatening, you may also have to make jurors doubt that you are guilty of any related crimes. This can take some intense work, so it is best to get the defense strategy started as quickly as possible.