I’ve actually had 2 priests chuckle in the confessional.
Once when I was really working on coming clean of past offenses…I actually had lied to a priest in the confessional when I was a teen and it was really bothering me. It was not a huge matter and I think Fr. chuckled before he realized he was doing so. He did give me some sound advice afterwards but he didn’t consider the trangression to be so big. (He probably thought it was “cute” that someone would bring up something so old)
The second was a couple weeks ago, and it was face to face. Within the context of the confession and discussion he kind of laughed at what I was getting at but told me where the sin was and explained to me where I had erred.
In both occasions, I was actually very much comforted by their laughter and did not have the sense that they were laughing at me at all.
The first priest is now my SD, and he does his best to not even smile when we are talking about a serious issue so as to not appear to be laughing. For example, when I first met with him and was relating an incident which had brought me to him, he sat as he customarily does in face-to-face confessions: with his hand over his mouth, making eye contact if appropriate, etc I noticed during our conversation that the corner of his mouth was at first twitching and he couldn’t quite hide a smile. He was afraid he was going to offend or distract me so I have to give the poor priest credit!
For the record, I would not have been offended but he likely did not know that at the time.
I have yet to send a priest into gales of laughter in the confessional, though, and for that I’m grateful. I’m sure it’s just a matter of time, though.
I think some priests in their experince are able to let go a little as in their experience they learn to discern what someone needs at a given time. Sometimes a little chuckle is just what is needed.