In the US neither side is required (in general, some exceptions appy) to give notice, or a reason, to terminate employment. For more senior jobs the custom is to give notice when you quit. Employers generally have a process of reviews and warnings that let employees know when they aren't performing, so getting fired without notice happens because of gross misbehavior or negligence.

Even if the employer has a habit of letting people go without notice or severance, it's still professional to give the employer notice. I think a person should behave ethically and professionally regardless of what the other side does. Of course sometimes the situation is so bad that walking out with no notice is the only choice, but in my experience those kinds of workplaces are rare and I had plenty of time to notice the dysfunction and plan a graceful exit.