Tangential question: Always been curious what is more challenging 1) Find interesting & original problems to research or 2) Doing the actual research? I can im

Tangential question: Always been curious what is more challenging 1) Find interesting & original problems to research or 2) Doing the actual research? I can imagine the struggles of the research. Does the thought "Damn! I should have chosen a different problem" cross your mind when researching (which leads to question #1)? PS: I am just a graduate with no intention of doing PhD.