It's true that they probably won't sue you for breach of contract, though they can, but if you just walk out of a job, you're at the risk of ruining your professional reputation, arguably the most precious resource. There aren't many other things that would be as much of a red flag when hiring as an employee that just decided to walk out of a job.

Of course if you have good reasons to stop working, there are good options. If it's stress or similar mental health issues, you can resign and spend your notice period on sick leave. If your employer assaults you or just stops paying, or otherwise grossly neglects their duties as an employer, you're legally entitled to quit immediately.