We take decisions on a daily basis. Small or big. Decisions have short term effects as well as long term implications. My professor used to explain there are three types of decisions - right decision, wrong decision and stupid decision. But often we wonder why did we decide so, or if only we decided differently the implications would have been better (or worse). It is not uncommon for a person to repent on his decisions.
Biologically, the electrical impulses which sometimes manipulate the brain are caused by over secretion of certain hormones. This explains the mob psychology and most unplanned criminal activity. Otherwise poor decisions are taken due to lack of sufficient information or under the pressure of time.
I think decisions are spatiotemporally influenced. No decisions are wrong at that particular space and time. Provided enough information is available, all decisions taken are right decisions. Later when the space and time differs these decisions appear stupid. Wise people accept that as a stupid decisions and move on; but psychologically blind / myopic fellows (say, fanatics) just follow them.
So next time when you make fun of stupid decisions made by others (or by you) remember, those were right decisions, when those decisions were taken. Grow up, accommodate and do what is best for you in the present.