Adults can and do make friends but it's a different process than children/teens.
As for bullying, yes I've experienced it. When I was in my 20's I had become certified as an EMT. My first job was with a contract company with multiple locations within a county. I was fully qualified to do my job but I've never been very good at managing social situations so it wasn't long before the "she's weird, I don't want to work with her" talk began. From there it was all downhill. The last incidence of bullying on the job was my very last 9-5 type position. I had to share a very small office with another worker. As we both did the same job, we had contact with much of the same people. She would find ways to make herself look like the better worker by taking work away from me, talking with coworkers and supervisors behind my back to get special assignments. All of this to make me look worthless or redundant. It got to the point where we would sit in our office together and not say one single word to one another. Not even hello or goodbye. I was so glad to leave that job.