Consider the phrases: “I can’t do that.” or “I have to do this.”
Yes you can. No you don’t. These are nothing more than crutches of language.
What someone is saying when they claim that they can’t do something is that they won’t because the ramifications of their action would be unacceptable, like losing their job due to breaking company policy. I won’t get offended if you like your job more than you like me (that would be unreasonable, we’re strangers), just tell me that and then let me talk to your manager. Can’t is asking a quadriplegic to walk, asking a blind person to read printed text, or being asked to break the laws of science and math. Can’t is a inescapable restriction, won’t is a decision.
Likewise there is nothing you have to do. You don’t have to take that final, you’ll just fail the class if you don’t (I’ve done this, it’s not as bad as you think). You don’t have to go to work, you just might lose your job. Losing your job or failing your class will not kill you. You want to work so you will have money, so you can sleep on a bed. You want to study (as hard as that is to say) so you will pass your courses, so you can get out of school (or stay in it more, I guess). You don’t have needs, what you have are wants of varying importance.
You can skip that final. You do not have to go to work. You don’t need those boots all the popular girls have. Grow up and stop lying to the world.
^ In fact, even things required for life aren’t something that can be called absolute needs. You don’t need to live, you just want to (so do I!) so eating and breathing are reasonable expectations, but not actually needs. Needs are completely relative to context. There are needs that must be fulfilled to sustain life, there are criteria that need to be fulfilled to be considered fluffy. Without a context, “need” is a meaningless word.