The primary danger is that you might end up in jail. You are in a dark alley, someone tries to mug you, you shoot them dead. No witnesses. Police find a lot of

The primary danger is that you might end up in jail. You are in a dark alley, someone tries to mug you, you shoot them dead. No witnesses. Police find a lot of money and some drugs on your assailant. They suggest that foul play was involved. A drug deal gone wrong. Under pressure you misremember certain facts of that night. The police notice a discrepancy in your story and build a case out of it. A second danger is that you might aim a gun but not be able to pull the trigger. A large percentage of soldiers in WWII found themselves unable to kill someone, even when their life was in immediate danger. Subsequently, armed forces spend a lot of time on psychological training to turn recruits into killers. You presumably haven't had this training, so I would bet money that you wouldn't be able to kill someone. A third danger is that your assailant might have a gun too. In this case, the fact that you are carrying a gun cannot help you if they point theirs at you first. It can definitely get you killed if they notice you are armed. (for the record, I didn't downvote you)