Public defender here, so the vast majority of my case load is criminal defense.
1. They interact with me like they would any other professional person like a doctor. Some clients listen to and take my advice, and some don't. But, generally, it's a very professional relationship. If a client doesn't treat me that way, we have to have a discussion about appropriate behavior. Some client want to treat me like a friend or counselor, but I have to (for the most part) put a stop to that behavior because I have too many clients for clients to call me and chat.
2. Strictly professional. There are clients that I like more than others, but I'm not going to become friends with any of them. Also, whether I like a client more or less doesn't matter as to the quality of representation I provide for their case.
3. Of course I have personal thoughts about my client's cases. Sometimes, it's appropriate for me to share those, and sometimes it's not. If it's not, I don't allow them to show.
4. Yes, I have believed that because it happens all the time. If I have a client who I think is innocent that is convicted, it doesn't feel great. I look back and think about if there is anything I could have done differently or better that would have led to a different outcome. If yes, I try to keep that in mind for the future. If no, I move on. No one would be served by me beating myself up for past mistakes or past outcomes I didn't like.
If I have a client who I think is guilty and they are found not guilty, or the case is dismissed, it makes me happy that I was there to force the state to meet their burden, and that led to a good outcome.
Which brings me to an important point. It doesn't matter if I think someone did it, the State has the burden to prove every element of a crime beyond a reasonable doubt to convict someone of a crime. If the State can't do that, even if I think the client did it, they should be found not guilty. A not guilty verdict doesn't necessarily mean that the person is innocent, just that the State did not or could not meet their burden.
5. I love my job. I get to help people navigate the fallout from what was probably one of the very lowest points in their lives, which can be very gratifying. Additionally, I work with a team of very talented and dedicated attorneys.
I'd be happy to answer follow up, but it may take me a few days (I'm a bit busy with my caseload).
EDIT: Sorry for the weird formatting, I'm not sure how to fix it.