Son, desist from show off. It is like doing ‘Shirk’. It is said in the tradition that one who does deeds to show-off to others (except Allah), Allah will return it to him on the day of judgement.
‘Show off people will be called by 4 names on the day of the judgement. “Fajir”, trailor, kafir and ‘Khasaratkar’. His deeds will be useless and he will not get any reward. In the end, his deeds will be given to one whom he wanted to show-off.
(Wasael-1, p. 11)
It is related in some tradition that when a person does a small deed for Allah, Allah magnifies it in the eyes of momeens and if a person does a big deed to show-off, then Allah makes his deed small even though he might have become tired by keeping awake the whole night.
(Usul-e-kafi-2, p. 216)
It is against common sense that a man offers prayers to Allah in public while in reality he is praying to show others except Allah. What is the benefit of such prayers, which is to show public? Poor man, who cannot kill a mosquito, what he can give to others? One who cannot snatch a thing which a bee has taken away, what one can hope from him? What would you gain by pleasing him?