Part-time faculty are normally less used with the prerequisites for courses taught in their departments, hampering their capacity to counsel students effectively.
I think this is the biggest issue I have outside of the low wages. I adjunct at a low income minority private university where my students have a lot of external factors affecting them. I had a student on probation. A student who did not have bus fare. A student who was a mom of two. They were all under the age of 20 years old. I needed to set time aside to address their limitations and how I can help them overcome them but it took me taking extra time out of my schedule to be able to do so. Otherwise they would have dropped out or failed.