I pick up doughnuts for the office about once a week. The nice lady at the doughnut shop knows me and occasionally gives me an extra doughnut for free and since she knows when I usually come in and what I like, often there is a fresh batch just before I happen to show up. Bribery or just good customer relations? Well, I like that doughnut shop allot and am very inclined to give them all of my doughnut business.
In my business? We sell "parts". We have regular customers and irregular customers. When a good regular customer calls and says they absolutely HAVE to have their parts by the 15th of next month, we put people to work overtime, reschedule other jobs ect ect, whatever we have to do, to make sure they get their "parts" by the 15th of next month. We make it happen for them. OTOH, if an irregular customer makes the same request, we may profusely apologize that we just cannot meet that deadline.
Business is business. Businesses of all stripes everywhere in any line of work do well to give preferential treatment to their best customers.