If I'm reading something then its hard for me to drop it unless something really bad happens. For me that would be when the story completely goes off the rails and denies a few basic things that have been 'promised' or if it just ends up being sooo generic that it would be pointless to view it any further. The latter mostly applies to isekai slop but do they even count if I can't even remember the name?
What is your favourite completed manga that might appear simple like the many others of it's kind but actually has a great story, characters, humour, etc without getting boring and stops at a satisfying conclusion; which you would like to rate above 9/10?