A goodbye letter and an invitation to farewell party

Dear my beloved friends,
It's really hard for me to write you this post but what I am trying to present hereunder is to inform you that I am leaving our class (not leaving you:D) since tonight.
Firstly, please accept my sincere apology for any inconvenience or disappointment my absence may cause. It's not only my new job, my new plan, my new intention but also my new thinking about what I am going to do in the coming short-term and long-term run. The decision to quit a certain goal must be an accumulation of intention and careful considerations. However, what I did, as I once mentioned, might possessed an important part of personal and emotional judgment. I cannot guarantee it is the best, or at least a wise choice, but what I believe now is that, it is a right choice that I must follow.
That's quite a lot about "me" and might show my irresponsibility about the class, but my leave can be a good case for you, I think. We can't ignore the fact that the quality of each meeting has showed poor preparation from the members. More importantly, the effort we spent on self studying and improving our test taking skills, and English as well, has not been good enough. Each of you has a different expectation of the outcome, but I wish that you can arrange better class from now on, given my absence.
One thing I can tell you confidently is that I see the strong inner motivation from many of you. That's really the fresh desire for personal development and the good for the future. It's good that you have it now but it's really a great pity if you lose that desire in the next few years when you put your feet on the professional workplace. What we finally appreciate ourselves is not just about how happy our family is, not about how much money we gain, or how big our house is, or... how fast and expensive car we drive,... as many young Vietnamese professionals are going crazy for now; but how much we are really being sincere to ourselves and how truthful we express our actions to achieve our expectations.
and.........
I would like to invite you to a small farewell party tonight and I hope you can feel better by switching a regular bland practice to a speaking opportunity with delicious food. The party, with your permission of course, will be decided by the board of members at Summit - our frequent place and at the frequent time 6:30.
More interesting stories to be continued....
Yours,
Huan Le