People are crazy for them and end up doing things like buying expensive gifts and sending it to them just to get their attention. They stick their pictures in their rooms and sketch their faces, write poems on them, etc. Some people also end up hurting themselves when they don't get the attention they want from their favourite stars.
Film stars get too much attention in India. They are just normal people and all the attention they receive can make them feel too self important and look down on others. The same is true for professional cricketers in India. They happen to be very good cricket players, but they should get attention for good deeds, not simply as celebrities.
The benefits of Bollywood actors and Cricketers being over popular are much better than the consequences. Though it may be leaving people jaded and not into Indian culture like the good 'ol days, Bollywood will lead to Hollywood roles, money will come into India, and a trickle-down effect will occur to help out the poor and needy in India as Hollywood stars give money.