A hardship, like close to poverty or a tragic accident or illness can greatly affect someone's outlook on life, therefore affecting their identity. Once something bad happens to someone, it can turn them from being a positive, optimistic individual to someone who has no hope or motivation to do anything. This then reflects on to how they present themselves; impacting their identity. .
If you studied the difference between a teenager who was brought up in a Canadian home, whose parents were well off and had it fairly well, and a teenager who was brought up in the poverty driven part of the United States, you could see a great difference in their attitude and identity. Due to the different environments both teens are in, it affects their personality, their views/morals, and their identity. Living well off becomes a norm for you and you don't know anything other than that, while living in poverty is a norm for the other person. What surrounds you from when you were younger will affect who you may be come in the future. How you act in certain situations, how you adjust to new places and who you become, what you know as your identity, starts in where your main environment is. .
Another aspect of the environment you are surrounded by, is what you exposed yourself to or what you become exposed to. If you are exposed to a party, careless, irresponsible atmosphere that could lead you to make similar choices later in life. If you are exposed to intellectual aspects like books, computers, and learning very early it can lead to a desire or passion for learning leading to higher intelligence. Also, the habit you develop from when you are young or the habits you observe, can reflect onto you during adolescence. You could be known as the perfectionist, because you took on the habit from watching your mother make sure everything was always done right and perfect. You could be known as the lazy laid back individual, because no one pushed you to try harder and you didn't put much effort in as a young child.