Imam Khomeini sheds light on the subject as following:
Zurarah reports that he questioned Imam al-Baqir (A) about the status of a person who performed good deeds, which were seen by others and it made him happy. Said the Imam (A): There is no harm in it; there is no one who does not like that his good deeds be made known to the people, in case he does not perform them [solely] for the sake of attracting their admiration.
In one of the two ahadith, the tendency of performing good deeds for the sake of earning respect and admiration is considered as the sign of riya’, while in another hadith it is stated that there is no harm in the joy resulting from the demonstration of a good deed.
These two different positions are taken in view of the category to which an individual belongs. There are certain other reasons also for such a view, but we shall abstain from mentioning them.