an 而 question

[murrayjames]

At a car wash there's a sign that says “高兴而来，满意而归”

I take this to mean "Come here happy. Return (home) satisfied." Is my translation correct? What is the function of 而 here?

[Don_Horhe]

Yes, your translation is correct. In the example above 而 connects the head with a preceding modifier, and in this particular case is quite similar to 地 linking an adverbial adjunct with a predicate. This usage of 而 is mostly prevalent in 成语's like 半途而废 "to give up halfway" and 满载而归 (lit. "to return fully-loaded") "to come back (e.g. from studying abroad) with good results/achievements".