I had the same feeling of euphoria after riding at night in the rain. At first it is a terrifying experience and you question your sanity, but once you get a bit of confidence the fear recedes and it can be fun. Don’t like doing it in traffic though. The cars will be right on your ass as you take corners which is an unnerving experience. I found 60mph to be my comfort zone. Any faster and I worry about hydroplaning, but when I saw an 18 wheeler catching up with me one night I made dam sure I got to my exit before he caught up with me.
I also found that riding around suburban neighborhoods in the rain a challenge. At less than 30mph, RainX or no, the water was not shifting from my visor right when I needed the best visibility to avoid those driveways and side streets. I ended up riding with my visor up as that was the only way I could see. And I was very aware that the visibility of those in the cars suffered as well so I was on high alert.