In the majority of modern homes, you won’t see a wall receptacle without a ground, but in older homes these could still be around. Even worse, there are some homeowners that have done a little DIY and replaced the old receptacle with a new, grounded receptacle without the proper ground to connect it to. This could create a false sense of security when the receptacle actually is a hazard.
There are many things that don’t operate properly without a ground, even though it might not be obvious from the beginning. For example, if you have a surge protector to keep your electronics safe, it won’t do its job when a surge comes through, which could lead to a huge loss. Some appliances could become lethal if there is a short and there isn’t a ground. Unfortunately, it is very difficult for you to figure out whether or not a receptacle has a ground. You might need the help of an electrician to check it out, especially if you don’t have the experience to know what to look for.