Watching a silly comedy that most of the audience appears to be enjoying, but which you find pointless, plodding and excessively broad, can be a frustrating and bewildering experience. You wonder, why can’t I get into this? Is it me, or is it the play?

That was my mindset sitting through all 100 intermission-less minutes of John Patrick Shanley’s new romantic comedy “The Portuguese Kid,” which just opened Off-Broadway.

Shanley, who is also directing the production, has enlisted a fine five-member cast that includes Jason Alexander, Sherie Rene Scott and Mary Testa.

This marks the 12th play by Shanley to be produced by the nonprofit Manhattan Theatre Club. Among those plays, there have been highs (the masterful, Pulitzer-winning drama “Doubt”), lows (the awful musical “Romantic Poetry”) and a lot of in-betweens (including recent works like “Outside Mullingar” and “Prodigal Son”).

In “The Portuguese Kid,” the hotblooded, unpredictable, two-time Greek widower Atalanta Lagana (Scott) seeks the aid of anxious attorney and old friend Barry Dragonetti (Alexander) in selling her late husband’s estate, while Barry’s imposing Croatian mother (Testa) views Atalanta with suspicion and delivers ominous warnings.

It turns out that Atalanta’s much younger, Italian lover Freddie (Pico Alexander) and Barry’s much younger, Puerto Rican, New Jersey-bred wife (Aimee Carrero) were a couple not so long ago. Although Atalanta and Barry have never been a couple, Atalanta has a curious habit of screaming out Barry’s name during sex. The partner swapping pattern that follows recalls the Sondheim musical “A Little Night Music” (which was based on Bergman’s “Smiles of a Summer Night”).

The play relies heavily on one-liners (many of which are labored and lame) and ethnic stereotyping.

Shanley employed ethnic characters to far better effect in his Oscar-winning screenplay of “Moonstruck.”

A few days after attending the production, I made a point of reading through the script and found it a slight but cute and well-meaning romance, which makes me suspect that the play may fare better under a different director who does not encourage oversized performances.

Scott, for instance, is so aggressive that it becomes distracting.

Alexander (who is relatively downbeat and grounded compared with everyone else) was a Broadway veteran before he won fame on “Seinfeld.”

Here’s hoping we see more of him on the New York stage in the coming years.