I had a bad previous experience with flow of ideas. I received a fellowship for six months to work on a project. I started on the project. I was very active and attentive with my supervisor who was very supportive and flexible. I worked very hard, but after two months many new ideas accumulated and I started trying on the dataset and searching for new datasets, after two more months, I had a shallow understanding of all of these ideas. It was late to focus on one point and I got depressed and I ended the project earlier and my supervisor told me I wasn't focused and I didn't do the tasks she suggested and my body language reflects I am not even listening to her (as I say OK a lot) and she will not write to me a recommendation letter.
I am now working on a master thesis with a new supervisor who is nice and flexible. As usual, I started working very hard, but having this terrible anxiety of losing control on the topic and after one month of work, I found that the idea I am working on, will not lead to a real advancement in science, so I changed my mind and changed the research idea a little to what I believe might benefit science. But I fear to discuss with her, because I know after another month, I will have another idea.
In brief, the first problem is that I lose focus not only because other ideas are attractive but also because I feel the idea I am working on isn't worth my effort and there should be an improvement. The second problem is assuming it is right to move between ideas, how to communicate this with the supervisor ?