Hail fellow well met
"Hail fellow well met" is a somewhat archaic English idiom referring to a person who is sociable and always winning friends. The Oxford English Dictionary (OED) gives a 1589 quotation for this phrase as a friendly greeting. The OED also gives quotations for the related phrase "hail fellow", a greeting that apparently dates to medieval times. "Well met" appears to have been added to the phrase in the 1500s to intensify its friendliness. This additional term seems to derive from the concept of "good to meet you", and also from the meaning of "meet" as something literally the right size for a given situation.
The idiom is rarely used as a greeting in modern English, but rather as a description of a personality type. Modern use of the term tends to be deliberately archaic, with overtones of over-familiarity or insincerity in the person (almost always male) so described, or as a deliberate, tongue in cheek term of endearment. Ir can be used as a pejorative as a description rather a greeting. The OED gives an example from the 1600s of the use of "hail fellow" as a description in a similarly pejorative manner.