There's no point in dwelling on it

What is the best & most natural way of saying this in spoken, colloquial Greek? It is a very common statement in U.K. English.

Μην πλατειάζεις / Μην το ζαλίζεις το θέμα
Δεν υπάρχει λόγος να ~ / Ποιος ο λόγος να ~

an instant suggestion

(PS. That's the meaning, isn't it?)

...
Besides the good suggestions by M_A_A_ above, my first thought was:

Δεν υπάρχει λόγος να το παιδεύεις / να παιδεύεσαι... Μην κολλάς σ' αυτό...

Well, two and a half thoughts, 'cause I'm dwelling on it.

Δεν έχει νόημα να εμμένεις / να το βασανίζεις / να βασανίζεσαι...

Thrice for good luck; fourth and fifth for amuck.

Thanks both. It means, m_a_a, 'there really is no benefit in reliving past experiences over and over again.':)

Ah, my bad then.

I went with this definition: http://dictionary.cambridge.org/dictionary/english/dwell-on-sth

In the sense you mean it, I'd probably say something like "Ποιος ο λόγος να τα αναμασάς;"

Your definition, m_a_a, is certainly one of the possible uses of this expression. I should have given example sentences. Thanks again.

Ναι, μην το κουράζουμε άλλο πια...


Αποφάσισα να βάζω και χρώμα εκτός από τα πλάγια για διευκόλυνση όσων βλέπουν από κινητά κλπ. συσκευές.

If we insist on the sense of 'dwelling on the past', we might say "Δεν έχει νόημα όλη αυτή η παρελθοντολογία".

But I too prefer the more general sense, and like the renderings: Δεν έχει νόημα να το παιδεύουμε / να το κουράζουμε...

Or, dr7x-like: Δεν έχει νόημα να το παιδεύουμε / να το κουράζουμε...

To sum up (and hopefully clarify).

Μην πλατειάζεις: not so colloquial - suitable to be used in refernce to somebody's speech, as in the example provided by Cambridge Dictionary. Searching for the term in third person (πλατειάζει) on Google News will show you that is chiefly used in book/movie/theater reviews. "...χωρίς να πλατειάζει σε λεπτομέρειες..." (without dwelling on details) is certainly said as a good thing.

Μην το/τα αναμασάς: this is a phrase I would opt for without really thinking about it if referring to something a bit more personal. "Reliving past experiences over and over again", you say, and that doesn't really sound like a context where I would use "πλατειάζω"... It doesn't really qualify for one's own experiences; "αναμασώ", on the other hand, does...

I'd say that "μην το βασανίζεις" or "μη βασανίζεσαι (μ' αυτό)", as Daeman suggested, is pretty close, in this sense.

I'd also say that the rest of the suggestions provided are more sort of all-around terms that can be used in either case, despite their marked differences "register-wise", so to speak: "Μην το ζαλίζεις..." or "μην κολλάς σ' αυτό" are certainly more slangy than "Μην εμμένεις", which sounds a bit "stiff" to me, whilst "μην το κουράζουμε" falls probably somewhere in between, but they're all pretty wide semantically...

In the very specific sense mentioned by Theseus ("reliving past experiences over and over again"), which I ignored as a distinct sense of "dwell on sth", I think that the expressions most commonly used in Greek for "there's no point in dwelling on it" would be: μην κολλάς σ' αυτό (already mentioned above), μη στέκεσαι σ' αυτό and, most of all, πάψε να το σκέφτεσαιand ξεπέρασέ το.

And sometimes you might find another idiom suitable: περασμένα ξεχασμένα.

:)Thanks to all of you for this plethora of suggestions! The trouble is for a learner to know the linguistic register of a particular word or phrase. All the information here has been invaluable & the sentences given are very instructive.:)