I've worked in other mediums (media?) but have found a strange quirk in myself that is really irritating - I fiddle. Yes, I play the violin, but I also just keep nerdling on things forever. When I work in traditional oils, I would keep going in and redoing things until all I had was just a mess. When I started reverse painting on glass, I was not able to keep fiddling with the work and finally it would be finished.
Why? Well, reverse painting is done the opposite way of traditional. I *start* with the foremost details and then work my way back to the background color. I have to sign the painting near the beginning, and as each layer goes on, the previous layer is covered up on the glass and so I can't go back and work it anymore. It forces me to complete the painting. If I finally decide that the painting just isn't working, I have to scrape the whole thing and start over. The pain of doing that is usually too great, so I just let the painting be what it is and move on to the next.
The same is pretty true with glassblowing. Of course, we plan out the colors we will use and the basic design and shape and function, but as the glass is molten, we can't go in and really tweak anything if it's going different from planned. Sometimes that's the best thing too! We'll be working on a specific design and the glass will start to go a different direction. We are learning to be flexible enough to say OK and take it in the new direction to see what it wants to be.
This has been a really hard thing to learn too, to NOT force control over the glass. Sure is fun and cool when it works though!