I had an actor friend who was tapped by a medical school (??) to give their student-doctors-in-training practice in diagnosing illnesses. His illness was necrophilia, but of course, he wasn’t allowed to say so… they had to figure it out during the course of questioning, and when relating the story afterwards, he thought it was hilarious when understanding dawned on the students as to what his affliction was.
Same thing is true with priests. They go through some very rigorous training in order to be “let loose” in the confessional, in a manner of speaking. You get effective priests, with good insights, who talk about not just your sins, but what underlies them and makes you susceptible to those sins… and how to address the bigger problem, and tailor your penance to your problems. You also have less effective priests, like those who just tell you to say a “Hail Mary” in penance for what you’ve done, no matter what you brought into the confessional. You occasionally get the priest who has the grace to always manage to say just the right thing-- and they have no clue as to where those thoughts came from, but they were exactly what you needed to hear to get you on the right track. And then you have a wide range in between. But they all have to practice before they’re ordained-- what do you do in this situation? How about that situation? What do you say when someone comes to you with this?
Regarding that training, I’ve known multiple priests to talk about it, and they laugh whenever people ask them if they’re ever shocked by what they hear. It’s pretty much impossible to shock or embarrass them. They know quite well what people are capable of doing, and probably get a wider experience of life and society than most ordinary people do.
Regarding contrition, the general feeling is that it’s not for them to judge… it’s between them and God. I once heard a woman speak on how a religious experience during her NDE changed her life-- she gave an anecdote that went along the lines of someone asking her, “Why did you give that homeless guy $5? He’s just going to spend it on liquor or drugs.” And her answer went, “It was my choice to be charitable. I did my job. Whether or not he puts my charity to good use is ultimately between him and God.” The same thing is true with Confession… the priest is acting
in persona Christi. Confession isn’t about the priest at all; he’s just sort of the visible intermediary. So it’s his job to hear confession, give counsel, prescribe a penance, give absolution, but it’s not his place to judge. Whether or not the person made a good Confession is ultimately between him and God; he’s done his job.
Regarding frustration, I think the penitent is more likely to be frustrated by committing the same sin over and over again than the priest is at hearing it. One thing I have heard from priests is that often times, they genuinely have no recollection of the specifics that are confessed to them in the confessional. I don’t know if that’s true for some of them, or all of them, or what.
Regarding day-to-day life, there are plenty of blogger priests.

You might do a Google search to get a good cross-section of what their days/routines might look like.
And this being CAF, I’m sure it won’t take long for a few real priests to chime in with some better firsthand answers than mine.
