I decided to finally share my GMAT experiences. I am applying for pre-master program, it's like a one year 'bridge' program between college and university before you actually start the Master degree. It's not for MBA but its a MSc. They asked for a GMAT score of 600 as a minimum requirement and passing their Mathematics & Statistics entrance exam. I passed both Math & Statistics exams, so it's okay.
I am not a native English speaker, but I am quite confident because my business degree is in english language and got used to writing essays and reading articles in English language. I switched from full-time job to part-time job to prepare for GMAT.
I took two GMATs. For the 1st test preparation, I studied the GMAT Official Guide (OG) book, ManhattanGMAT 8 books, practiced the free tests from GMATPrep and practiced the tests from 800score.com. In practice tests I got score between 480-520. I knew that, the night before the real test, that this would be a difficult goal to reach 600, but I did it anyway. I was shocked to get only 400, so I decided to retake the test in one month.
After this 'reality-check', I studied harder by following the guidance from ManhattanGMAT books, redo the questions in OG, and practiced more CATs, this time I also did the tests from Gmatclub. I studied my mistakes and tried to understand the correct answers. I followed and practiced the methods from ManhattanGMAT, which in my opinion are excellent and easy to understand.
I read this forum and tried to boost up my confidence and motivation. I read the news online everyday from BBC and CNN in every section from business, tech, environment or regional. I even read articles from Nat Geo because I always interested in articles about stars, planets, fossils, etc.
Eventually, in practice tests I got score of 550-580. It was still not enough, but I have a feeling that the University would still accept my application, because it is the first time they require GMAT score from applicants. They said that 600 score is certain that applicants will be accepted, but below that they would have to consider the grades/GPA.
So, at the test day, I felt confident but I was still a bit worry...what if I scored below 580? will they still accept my application? but oh my...I got a score of 460, unbelievable!

I was shocked...and deeply frustrated. I can't be this stupid. I went home feeling depressed and hate for GMAT because this was my last chance before the school starts in September. I went home and started writing motivation letter and sent it to them. I need to wait for 1.5 weeks for them to be able to read it because of summer vacations.
Yesterday, I received news from the University that my application was rejected because I have insufficient GMAT score

I have wasted a lot of time and a huge amount of money. I wasted my efforts and feelings. I've got little social life during my preparation. Now my whole plan is ruined and I've got serious personal problems with my girlfriend because of this.