Eve did the same thing in reply to the enemy creating doubt in her mind....and then she even exaggerated further what God said...which wasn't so.
But I think most are more like Adam...they simply prefer to go ahead without consideration of what God has stated. It's 'easier' doing it thier own way...thus they have the sense it's "their" trophy of accomplishment...."You will be like God" sort of thing.
I think you should take another look at the 1st Adam. Remember that the 2nd Adam 'knew no sin, yet became sin that we might become the righteousness of God' (2 Cor 5:21)
I'm thinking that Adam was trying something similar to save Eve, whom he loved. The final fulfillment (Christ) being visible in the initial appearance (Adam).