*One should not ask about the source of the food that is offered to him. It is mentioned in the hadeeth that the Prophet () said:
'If one of you is invited to his fellow Muslim's house, and he serves him food, let him not ask about its source. If he gives you to drink, do not ask where he acquired it from.'(Ahmed) *It is praiseworthy that food is given in equal portions to all those in attendance.
*It is praiseworthy that one eat from the sides of the plate and not from its center. The Prophet () said:
'Eat from the sides of the plate and do not eat from its center, for indeed the blessings descend onto the food from its center.'(Abu Dawood) *It is praiseworthy for one to use three fingers when eating, and to lick his fingers after finishing his meal. Ka'b b. Malik () said that the Messenger of Allah () used to eat with three fingers and would lick his fingers before wiping them. (Muslim)
The wisdom behind this is that one does not know where the Barakah (blessings) are. (Muslim)