I feel like bailing on volunteer work for my class competition.
Why do you not want to volunteer?
It's a waste of time and it's going to be too long
It's wrong not to help out if you have time. You should do what is right and volunteer for your class.
Yeah, but I don't want to. It's my choice whether or not I volunteer.
You're right, volunteering is your choice, that's literally in the definition. I'm just saying that it would be nice for you to help your class, and if you did they would probably be quite grateful to you.