I'm thinking of quitting a job I hadn't started yet
Why do you think it's a good idea to quit without even starting first?
Because I'm too lazy to start it
I think you should at least give the job a shot first.  You can't properly determine a job's worth working if you haven't even worked it yet.
I know the job is going to suck.
I think it's wise to just do the job for at least a month and see if you don't like it. You never know if it would actually be the perfect job for you!