I'm going to call out of work to dj a wedding
Why would you not go to work in order to DJ?
I'm there to make the people there happy and to help them have fun
You're expected to honor your work commitments.  If you know in advance that you want to work at a wedding one day, you should let your company know that you are taking time off for yourself so that they can plan ahead.
It's okay if they don't like me. There are other jobs in the world that I can just go to.
There might be other jobs, but it is wrong not to honor your commitments to work. This will be reflected on your references the new job gets from your old one. They will think you are not dependable and not get hired.