I do believe that to be happy implies a lot of self-bullshiting. You can not see the world clearly and still be confident in yourself, in the fellow man, in the future and your abilities. Weather we like it or not, a little lying is necessary. So when you chose to look at decisions in any kind of isolation you are lying to yourself. The lie is that everything is not connected. On the other hand, not accepting this lie leads to madness, mysticism or worse.

To be happy for me requires absolute brutal honesty about my situation. It may be upsetting in the short term, but in the long term it gives me clear genuine goals that are satisfying to reach.

When I've lied to myself historically about whether a decision I made was successful, its lead me down paths that weren't fulfilling and often resulted in failure. The best thing is to learn as much as possible about why the decision you made, that you thought was the best at that time, wasn't in fact the best decision.