It's common for heart attack victims to wait hours, even days, without asking for help. While they wait, heart damage is occurring. Also, the kind of discomfort associated with heart attacks can be mild. It might feel like pressure or squeezing, rather than pain. The feeling of discomfort may come and go, as well.
People deny to themselves that they're having a heart attack.
No one wants to be having a heart attack. They may hope they're only having heartburn, or simple muscle strain. Some people are embarrassed. Others worry if their insurance company will cover. It is always better to be safe than sorry.