if the above is not your circumstances and only an example, im intrigued to know what actually did happen?
i have had bad service and I have had good service. i have no problem stating who because it was only in my case, others might have found the opposite service. the service was not poor as such, more so the specific employee (at hff) i dealt with i found very rude. the good service i received (a couple of times at jansens) again was specific to the emloyee that served me (rather than a "company policy" type situation such as a refund on a bad purchase) the guy (on both occasions) was very helpful and keen to offer advice, even backing himself up saying the advice is from personal experience and i might find others may offer an alternative solution. no it wasnt you ben, but im sure you would be helpful too
i think you have to be careful not to fully judge a shops service if its based on a single employee. if the service is based on "store policy" it is a different story of course. i think the lfs should be quite clear on stating purchases, such as marine fish and their compatibility, to any purchaser regardless of their 'experience' in the hobby. even so, the hobbyist should be careful with their purchase before pulling out their wallet