The basic idea of all kinds of customer relationship management is treating different customers differently. If that may be the case, should we treat low value customers like second grade citizen?

 You cant. And that’s where CRM activities miss the bus. You cant give the CEO the window seat and company executive the aisle seat and expect them to be okay about it. The low value customers will never justify your move by saying to themselves “Hey, that guy gives the company so and so money so he should stand first in line all the time, and I should eat the humble pie and be delighted with mediocre service.”  

Even your least value providing customer won’t be happy with that. He will want the same level of service like your most value providing customers. That’s why if you give your most valuable customers the best seat, give the other customer something different to make up. Give him extra service. Smile more at him. Give him a free candy. It can be small, and less costly. But whatever it is, you have to make the less valued customer feel that he is getting preferential treatment like other more valuable customers.  

The trick is to make him feel like that with less cost.