The Indo-European word for 'honey', I have to confess, has always bothered me. Technically *mélit displays proper form with full-grade in the accented syllable and zero-grade in the unaccented and it also is supported by reflexes in Celtic, Germanic, Latin, Greek and Anatolian languages. Yet...
Douglas and Adams inadvertently uncovers a problem with this irreproachable hypothesis at the bottom of page 262 of The Oxford introduction to Proto-Indo-European and the Proto-Indo-European world (2006): "The noun *mélit is found widely in the West and Centre (e.g. OIr mil 'honey', Lat mel 'honey', NE mildew [< *'sweet sap'], Alb bletë 'honey-bee', Grk méli 'honey', mélissa 'honey-bee', Arm melr 'honey', including Anatolian, e.g. Hit militt- 'honey') and has one Iranian cognate in the form of a reference to melition, a drink of the Scythians."
Naturally we should ask: Why is the distribution of this word west and center? And you've probably surmised that I'm thinking of a possible Aegean explanation for what appears to be nothing more than a wanderword. A more valid PIE root for 'honey' might best be sought in the more-fully-attested root *médʰu, normally assigned the value of 'mead', a wine made from fermented honey.
What I'm pondering on is the possibility that only the Anatolian forms for 'honey' are truly Indo-European but which represent some innovative derivative from a native root. From there, Anatolian *mélit would be borrowed into Aegean as *méli with other related borrowings like *malítu 'sweet' (cf. Britomartis) which would in turn be borrowed into Greek. By the onset of the 1st millenium BCE, Proto-Cyprian *meli 'honey' and *mlitu 'sweet' would yield Old Etruscan *mel and *mliθ via early syncope. Once the Etruscans arrived in Italy, the early Latini could have easily borrowed the Etruscan term, thus Latin mel. These terms, along with their Etruscan-derived runes, could then have also travelled eventually to the Germani and among the Celts.
That would certainly explain the distribution a lot better than the standard Indo-European-based theory.