Scrum sucks when people ignore why they are using it and decide to use it just because everyone else is. indifference is usually the root cause of broken scrum. No one speaking up and saying 'lets fix this'. Things piled on for no real reason but not thrown out when they are shown to just be in the way. Throw in a 'bad actor' and yeah it can really suck but then the whole job will anyway no matter what your process. No one really wants to work with a grumpy person. That is not the fault of scrum that is a organization/people problem.