I'm thinking of quitting my job with only a few days notice
Is there a reason you do not want to give proper notice?
I'm bored and I'd like to try something new
It makes sense that you wouldn't want to be stuck in a situation that you aren't happy in. You have every right to quit and find a new job that allows you to be happy.
I have a good idea of where I want to work at next.
I think that leaving is fine, but you should give proper notice. I think that it is important to leave a job if it is not something that you really enjoy.