We always said that we want to do that, we wish to do so, why we did not do it etc. All these wishes are just useless actually if we did not do anything then at that moment of life we want to do the same. If you want to do anything and someone will inform you that you were doing wrong but knowing each thing you did that thing. Why we always ashamed on our deeds because we always think our self perfect. We always think that we are the super genius and whatever we did is perfect.
Same thing was happened in the case when Allah said to them to sacrifice a cow; then they start questioning and asked Musa to gave them the exact information about the cow. They asked about the age, color and other signs of the cow then on each question Allah informed them and the choice become more and more difficult and they find no way except to sacrifice the cow. The question was not just to sacrifice the cow the main philosophy is that the humans never accept any thing without objection.
Kindly read the verse of the Holy Quran as mentioned below:
" Musa said: He says, Surely she is a cow not made submissive that she should plough the land, nor does she irrigate the tilth ; sound, without a blemish in her. They said: Now you have bought the truth; so they sacrificed her, though they had not the mind to do (it)."
(Para No: 1 & Verse No: 71)
Allah informed us that the basic thinking behind all the stupid question is to linger on the procedure and find the way to avoid the sacrifice in any way. The human philosophy is based on the denial. We can object each and every thing. Every man has the right to criticize the believe of the others. One thing which is sacrificed for one man the other man think it stupid. We never stop any one to think different. It is the rule made by the Allah and He will solve all the difference between all of us on the dooms day.
No one can claim that the believe in which he is true, but i believe that there is One Allah and Muhammad (PBUH) is the messenger of Allah. I believe in the last day and also believe that one day i will be presented in front of my Lord. This is my belief and i am not appointed to any one in this world as a guard to accept my belief.