Hazrat Shaikh Moulana Muhammad Zakariyya (rahmatullahi ‘alaih) once mentioned the following:
One should bear in mind the following aspect. If one acquires something from someone without asking, nor having the desire and expectation of receiving the item from him, then there will be a lot of barakah and blessings in the item which one has acquired. However, if one acquires something from someone through asking, or after having the expectation and desire of acquiring the item from the person, then there will not be any barakah and blessings in such an item which one has acquired. For example, one sees a wealthy person and desires that he gives him something from his wealth, then this is regarded as ishraaf-e-nafs (desiring the wealth of others) and this is not permissible in shariah.
(Malfoozaate Hazrat Shaikh 1/44)