Somebody recently referred to "Something's gotta give" in my hearing as "charming". Hence this rant...
The essence of any rom-com is an ill-matched couple, kept apart by some apparently insurmountable barrier, destined to somehow be together by the end of the movie. "Sleepless in Seattle": they live on opposite coasts. "You've got mail": opposing political beliefs. etc. Age, culture, distance, class, political beliefs, disapproving families: something has to keep the couple apart for ninety minutes before we can all go home happy.
"Something's gotta give" offers us the unique sight of a romantic comedy about a couple who are kept apart by... absolutely nothing.
Harry and Erica are two independent, financially stable people of similar age, both well-established in life and successful in their careers. Both are single and unencumbered. Circumstances force them to live in the same house. Erica has no obligations as her adult daughter is self-sufficient. Everybody approves of their relationship, including Erica's daughter (who might have been expected to object since she had previously dated Harry) and Erica's ex-husband, with whom she has such a comfortable relationship that he drops by for coffee. Even Harry's rival in love, Julian, simply smiles and gracefully steps aside when the moment comes, accepting that Harry and Erica should be together. There's not a shred of conflict or difficulty or incompatibility in this entire setup.
The only reason they're not a couple after the first five minutes? "He only dates younger women", the other characters repeatedly tell us, although this essential fact is something that the movie completely fails to show. We don't even get to see all of these alleged younger girlfriends until almost the end of the movie, and none of them is dignified with a name, let alone a personality, a story, or a motivation for dating him. We have to take the word of the other characters, sitting around a dinner table, that he is a desirable, eligible, notorious bachelor who was featured as such on the cover of a New York magazine. (I believe that "featured on a magazine cover" is what movies go for to illustrate that somebody or something is well-known when they can't afford the obligatory scene of Jay Leno telling jokes about their movie's subject: "How about that Harry Sanborn? His latest girlfriend is so young, he has to leave her outside when he goes into a bar!". Or perhaps there are some things that even Jay Leno won't do?) Oh, and there's also some business about her being too busy/vulnerable for a relationship, although again there's no reason offered for why.
And since the movie provides no coherent explanation for why Harry collects notches in his headboard, we also get no explanation for what resistance he is trying to overcome nor why he chooses to change. At the start of the movie, he doesn't date women his own age; at the end of the movie, he does.
Even the title of the movie falls flat. "Something's gotta give" implies that both of them have deeply-held positions that are incompatible and that one of them will have to "give". Harry could accept that he should date women closer to his own age; or Erica could... I don't know, become a younger woman?
Once Erica and Harry have met, the rest of the movie is just marking time until it delivers its unearned and emotionally flat payoff and pairs them off. There's not a single moment in the entire film that rings true, emotionally or dramatically.