why Islam prohibits praising people so much

Prophet Muhammad SAW said:"if a man praises you too much, throw dust on his face." (Sahih Muslim, Hadith No. 7142)

Narrated Abu Musa (RAA) The Prophet MUHAMMAD (PBUH) 

heard a man praising another man and he was exaggerating in his praise. The Prophet MUHAMMAD (PBUH) said:"You have destroyed the man."(Sahih Al-Bukhari, Vol No. 8, The Book of Al-Ada'ab, Hadith No.6060)

Abd Al-Rahman b. Abu Bakra reported on the authority of his father that a person praised another person in the presence of ALLAH's Prophet (PBUH) whereupon HE said:"Woe be to thee, you have broken the neck of your friend, you have broken the neck of your friend, HE said this twice. If one of you has to praise his friend at all, he should say: I think (him to be) so and ALLAH knows it well  and I do not know the secret of the heart and ALLAH knows the destined end, and I cannot testify his purity against ALLAH but (he appears) to be so and so."

(Your praise will kill you with pride and self importance. You may not remain humble servant of ALLAH after too much of praise is showered on you.)