Let's say that you are going to sit for a major exam in 3 months. Obviously, you need to study hard for it. There are times when you would feel stressed or frustrated at a particular chapter. Some activities have to be given up or reduced, like watching TV, playing football, online games, etc.
It is all about balance; you can't lock yourself up in the room mugging everyday. There are other things which you would indulge in to keep yourself from going crazy. Life is not totally unbearable or miserable.
Another scenario. Let's imagine you have cancer but it is in its early stages. The doctor said that you would have to go through chemotherapy. As such, you have to go the hospital every 2 weeks for the session. Besides the inconvenience of travelling to the hospital, vomitting, wearing a cap to cover the thinning hair and feeling lethargic, you still go about, as much as you could, with other things like shopping, watching movies, hanging out with friends, chatting online, walking the dog and bullying your younger brother.
Now, it's after the exam. You feel very relieved, as if a big boulder has been lifted from you. You feel elater and can't wait to do all those things you missed doing. Still, the feeling will probably last a couple of days to maximum a week.
For the second scenario, fortunately the chemotherapy worked and you recovered after a year of chemotherapy. In a couple of months, you have regained your strength and back to doing everything you had been doing before that. It was as if you never had cancer at all.
Let's do an experiment. Assuming you are a reasonably happy person, not those who always whine and why-does-it-happen-to-me-God kind of person, your normal happiness should be more than 5, say 6 range on a scale of 0 to 10. The perpetually unhappy people would below 5.
If you, the exam-taker, were asked how happy or unhappy during his pre-exam preparation, you would probably say you were stressed, but not too bad. You still have online games and MSN when you need a break from revision. You would probably say 5.
If you were the cancer patient, you would probably complain about the tedious and painful process of chemotherapy, but those do not take up a significant part of your life. Probably another score of 5.
Now if you were asked how happy you were 1 day after your exam or after you are cancer-free, you would probably answer 8 or 9 or even 10. This makes sense, as you would be very happy with the end of the exams or conclusion of chemotherapy.
A few days later, your happiness would have fallen to your normal happiness level of 6. But if you were asked to rate your pre-exam period, you would think of the stress, no television watching, the late nights and all the negative things. You won't recall how you were reasonably at the time, but instead would now rate that period as a 4 or less.
Similarly for the chemotherapy period, you would quickly think about the pain and nausea, the trouble of going to the hospital and feeling weak and mostly all the bad stuff. You would probably rate that period as miserable as give it a 3 or 4.
The point is, you could not imagine how you could be as happy now as you were previously, when the circumstances were bad. Surely, you would think that you were so miserable then and things are much better now. Hence, my happiness should be lower than it is now.
An experiment was indeed done to demonstrate the above. Our memories are not accurate. We could never recall precisely what our feelings were. We could only remember certain things and that would override the rest of it.
Therefore, it is entirely possible for one to think that he is happier now than he was previously. Of course, it is also possible that you are actually happier than before. No one knows that for sure, not even yourself.
I believe many would not find this interesting. I know this and yet I have not find any application of its use. I used to think that I was not as happy as I am now, but now I am not too sure.
No matter, it is better to live in the present and be happy as you could be.