Why do Greeks break plates when dancing?

See: Konstantinos Konstantinides’ answer to Why do Greeks break plates?

As pointed out in Valya Doncheva’s answer to Why do Greeks break plates when dancing?, there are old folk antecedents to the practice—and indeed, similar practices are not uncommon among people who get drunk in general, as witnessed with any rock group that ever trashed a hotel room.

Per this article from the City of Athens Museum: Το σπάσιμο των πιάτων και η καθιέρωσή του

It seems that because of the financial crisis the custom of breaking plates at nightclubs is dying out, so we are taking care to recount it. Since time immemorial whoever came into a good mood (μεράκλωναν), especially at bouzouki clubs, would smash whatever they found at their table: chairs, painting frames, even pianos. Afterwards they would pay for the cost. So the number of those who’d pay for the breakage was limited.

[“Pay for the breakage”, πληρώνουν τα σπασμένα, is a proverbial expression. And it predates the Pottery Barn rule]

A clever businessman in the nightclub trade, Babaveas, opened the Folies d’été cabaret at the end of Herodes Atticus Road in 1931. With intoxicating Argentinian music, Parisian butterflies passing through, and a Russian ballet, he got his club into the centre of Athens nightlife.

The businessman would not charge his good customers for the breakage. But when the partiers (θεριακλήδες) increased in number, the old regime was restored. If you broke it, you paid for it, and you paid for it dearly. Three decades on, the custom was known, but it was not as well established or excessive. The spread of the phenomenon was aided by the movie Never on Sunday and the song The Lads of Peiraeus, in the early 60s. Plate smashing turned into a national pastime. That’s when the use of lower quality plates was established, whereupon the custom became daily practice.

Jules Dassin needed to reshoot the plate-smashing scene for Never on Sunday several times. He used defective plates that were factory rejects. In the 60s, there were up to 100,000 plates smashed per month, and some 50 workshops were established employing around 1000 people to cover the needs of partygoers (μερακλήδων). Later on they started using plaster copies of plates, to prevent injury and reduce costs.

Per Greek Wikipedia, Σπάσιμο πιάτων – Βικιπαίδεια,

Plate-smashing is a Greek folk custom, which reached its peak in the 60s and 70s. It was usual in nightclubs, as an example of Greek celebration. After it was banned by the Greek dictatorship, it retreated in the early 90s, but has made a return despite the financial crisis.

[…]

The only remaining workshop making plaster plates in Greece is Tsiourlis Bros. in Evosmos of Thessalonica, established in 1975. The practice of plate smashing seems to have been replaced by throwing flowers onto the stage, something inaugurated by the singer Marinella.

See also Plate smashing – Wikipedia, and Dimitra Triantafyllidou’s answer to What is the history of the Greek tradition of breaking plates and yelling “ooopaaa”?