Have you?

Have you spent a looonng time working on something and you felt so satisfied after completion. But later on, you found that you have made a small error but was too late to correct it and how did you feel? Do you feel like banging your head against a wall or feel like jumping out of the window? Have you felt like that? Or after your exam, you realise you forgot to add in this and that in your answer, otherwise your chance of getting a perfect score will be quite high. Have you felt something like that before? Have you? I always feel this way. Urgh.... Or is it my carelessness that makes me feel this way? I am a perfectionist in a way or another, provided I know I can get it perfected within my means. I yearn for perfection.
Anyway, I just realised that my C++ assignment did not produce the exact similar output as required. I did some changes to correct an error but resulted in another error which i did not realise before submitting. Although it's just 5 marks for the whole exercise and that mistake may cause me a small percentage of my marks, I still feel so URGH! Although I know getting a 5 out of 5 is near impossible for someone like me who is a greenhorn in programming. I still harbour that hope, since I have spent an entire week on it. How do I know I have made a mistake? I don't know why. Somehow, I always have the tendency to think about those stuff that I have done. Yah, what's done it's done. But I always recall and recall, think and think.... dunno for F***. I wish I don't but I just do. So out of the blue, this afternoon, I was trying to confirm if I have added some unnecessary stuff into my programming which may cost me some of my marks, then I found out another mistake I made instead. I was so down the whole afternoon just for that mistake. I did not check before I submitted yesterday. URGH. Now, I am listening to Kit Chan - 心痛.