Sorry, I probably haven't expressed myself clearly. I still believe (~60%) bupropion has some, small positive effects for me and that my mood would be even worse if I didn't take it. Here's a more detailed story:

I've taken this anti-depressant for quite some time, for around 8-9 months. At first I noticed a definite increase in mood and productivity (or so it seemed). I also tried to eliminate confounding effects and so stopped to take it for a week or so - and my happiness declined significantly! However, I was still concerned about placebo-effects so I made some "blind" tests (i.e. took capsules either containing bupropion or not, but without my knowledge which containing which). The next day I guessed if I had taken a mere placebo or not, and I was right about 85% of the time (n was only 7, but still...) 'cause my mood was worse when I only took a placebo. I also took two pills on some days and it felt like I had much more energy and was way happier. So Bupropion seemed like a true panacea to me.

Unfortunately, my mood started to decline around two months ago therefore I went to my psychiatrist and he doubled my dose. This was around a month ago but didn't really help.

I hope this clears things up! ;)