Dear Tom,
A quick note to say how deeply grateful I am for who you are and how you go about doing business. Simply put, I wish all my professional relationships were as rewarding as the one I have with you. Which, as I think about it, is a pretty odd thing to say about my computer repair expert for, without meaning any offense, calling you up to say “help” is never something I want to do. When I must call, though, I never fail to be impressed by your responsiveness, conscientiousness, and thorough professionalism. Then throw in that I enjoy simply hanging around you (even when my computer is acting up), and as I say, I wish all my professional relationships were as good.