1. It will take over many creative pursuits, taking away the feeling of usefulness from many people.
2. It will cause humans to be too independent from each other, and remove the sense of community (technology does this to some extent, only AI enhances the effect much more so)
3. It will concentrate wealth into the hands of tech companies, who relentlessly make life worse by continually making consumerism more efficient and thereby destroying our connection with the natural world
4. It will create disinformation and be a tool of manipulation and crime that will be hard to counteract (such as spoofing, etc.)
5. It will foster a world where there is far too much information, which itself plays on our basal instinct to collect information. This instinct was adaptive in the time of information scarcity, but is now maladaptive
And many other reasons....