My wife and I have had both savings and a mortgage with Nationwide Building Society for over 25 years. Recently we had cause to complain about their customer service and made appropriate representations.
To our surprise we received a well written, thoughtful understanding of our concerns and an apology for treating long standing customers like us badly.
It's a shame that this is such a surprise, but in the modern era it is comforting to know that there are firms out there that understand the proper meaning of customer services.
Another obvious example, and a regular shop for us is John Lewis