TITLE: On math looking obvious in retrospect
QUESTION [35 upvotes]: Admittedly, a soft-question.
I, being a very young researcher (PhD student) have personally faced the following situation many times: You delve into a problem desperately. No progress for a very long while. All of a sudden, you get the light, and boom: the result is proven. Looking in retrospect,  though, the result looks extremely obvious (to the extent you sometimes are ashamed of not getting till then, or embarrassed sharing/publishing). 
I wonder people's personal opinion on this matter (would also like to hear several real-stories on it, related to published papers). 
Note If moderators believe Mathoverflow is not the right venue for my question, I can consider relocating it.

REPLY [8 votes]: One issue to keep in mind is that things look obvious after you've been thinking about that thing for weeks, or months, or possibly years. Then when you have a proof, you think about how to present it, and how to generalize the idea in question. After all of that, the basic direction will seem more obvious to you than to someone who hasn't thought about it that much, since you've gone down the same mental paths many times. This also has a consequence in teaching; if there's disconnect for research, it may be even stronger when one is dealing with things one considers basic or obvious because you've used them since you were young.