If you would like to praise someone, you have to look positively to him. At present, the majority of people have a negative looks in their mind. Hence, they will fail in giving praise. Moreover, it is hard to wash those looks from their mind, especially, who are crossing 50 years.
Information retrieval from mind is the main aspect. If we can design a system that can allow for retrieving a positive information, I can say that we are able to give praise to everyone.