Some of my colleagues recognized the transition from student employee to professional, but strangely enough, my own boss never made the mental transition. She continued to treat me like a student in a number of degrading ways, offering condescending advice about preparing for my future and so on. I say this with a 20-year hindsight. I look back at the relationship and still think it was degrading. Within a year I applied to a different department where I got a fresh start and immediately was treated as an IT professional (though junior, of course).
I learned from this that some people are always going to see you like they first saw you. Your mother is going to always see you as the adolescent with the messy bedroom, even when you're 40. Your student job boss is always going to see you as a student.