It is getting demotivating to do css.I have heard that there are privileges but salaries are way much less.No one can join a service without having any worldly reason too.Some claim that going abroad is a far better option,life abroad is way much better.What are the privileges of this service which makes it special so that so many people want to do it.Do people just copy each other or are there any valid specialties of this service.

Well, you already know about the low salaries, then what attracts so many candidates if it's not money?
Following, in my opinion, are the different forces involved in making CSS a desired career:
i) Our colonial mentality ( being an ICS officer in the subcontinent was
so prestigious). Esp. true for some parents who want their children to
become CSPs.
ii) Some really want to serve their people, and i think CSS is the best
way to do so. For example, officers in PAS directly influence the lives
of thousands.
iii) Some want to prove their mettle as students (CSS officers are
considered creme de la creme of our society).
iv) Few have seniors,friends, or family members in the civil service who
act as a source of inspiration for them.
Each of us has different motives, but the above mentioned reasons need not be mutually exclusive.