Reading HP fan-fiction is a fairly hazardous pursuit for me since my favourite types of stories ('Canon Rewrite' and 'Peggy Sue') are also the most likely to include gratuitous bashing on my favourite character. Even the 'exclude' feature on AO3 only goes so far.
Here's an example. I was reading a really nice 'what if' story, wherein Lily ended up with Severus. It was going quite well and I felt safe since the summary had specifically stated that there would be no character bashing. Lo and