1. One should refrain from praising a person in public as there is the fear that pride may enter his heart. For this reason, the hadith has forbade praising people in public. Praising a person in his absence is permissible, on condition that one does not exaggerate in praising him.
عن أبي موسى، قال: سمع النبي صلى الله عليه وسلم رجلا يثني على رجل ويطريه في المدحة، فقال: لقد أهلكتم أو قطعتم ظهر الرجل (صحيح البخاري ، الرقم: 2663)
Hazrat Abu Moosa (radhiyallahu ‘anhu) reports that Rasulullah (sallallahu ‘alaihi wasallam) once heard a person praising someone (in his presence) and was exaggerating in praising him. Rasulullah (sallallahu ‘alaihi wasallam) said, “You have destroyed – or you have broke the back of – the person.”