It's not the boss you're hurting when you leave without notice--it's your colleagues. They have to pick up your workload without enough knowledge transfer AND still deal with the douchebag boss. Keep in mind that whenever you interview for a job, everyone on the interviewing team will look at your employment history, and if they happen to know someone who worked with you at any point, they're going to ask them about you. So if you intend to put your last job on your resume/LinkedIn, or if you end up interviewing at a company where one of your former co-workers now works, you're screwed, unless your colleagues are also jumping ship and sympathize with your plight (or better yet: see you as their hero).
It's not the boss you're hurting when you leave without notice--it's your colleagues. They have to pick up your workload without enough knowledge transfer AND still deal with the douchebag boss. Keep in mind that whenever you interview for a job, everyone on the interviewing team will look at your employment history, and if they happen to know someone who worked with you at any point, they're going to ask them about you. So if you intend to put your last job on your resume/LinkedIn, or if you end up interviewing at a company where one of your former co-workers now works, you're screwed, unless your colleagues are also jumping ship and sympathize with your plight (or better yet: see you as their hero).