Walking through the streets of the Upper East Side you see all sorts of things, smaller things that usually do not merit close attention, but that nevertheless make their contribution, for better or worse, to the larger fabric of the metropolis.

Just the other day, for example, I was on Park in the 70s, engaging in one of my favorite new activities: counting the scaffolding sheds along the avenue and taking a grim satisfaction in the mounting tallies. If this seems like an odd form of recreation, I would answer that there are few other satisfactions left on Park, given the proliferation of these scaffolds.

Among the most entrenched of them is the one that engulfs Lenox Hill Hospital, at Park and 77th. And it was only very recently that I finally understood the nature of the work that is being done.

Surely the building in question is one of the ugliest on the avenue. The hospital’s original wing, set in from Park along 77th Street, is quite an elegant Beaux Arts building and easily the best part of the complex. Unfortunately, through an inexcusable lapse in taste back in the 1960s, this wing has been reduced to a service entrance. Now the main entrance is a grim slab covered in flesh-tone plates that are among the most unappealing architectural features in the five boroughs.

For decades, I have been at a loss to explain what mind or eye could have sanctioned or conceived their installation. Well, finally someone shares my puzzlement. Ed Meirowitz of Consulting Associates is now replacing them with flatter, more rectilinear plates of a silvery hew, which will enhance the overall appearance. Without the Mod irregularity of the plates that are now there, these will err mercifully on the side of mediocrity rather than of total tastelessness, and so the avenue will become a little better in the process.

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Though the Mod style that inspired those plates has been responsible for some of the least impressive buildings in New York, one of the few landmarks of the style, at 27 E.79th Street, has just been destroyed. Designed by the Austrian architect Hans Hollein in 1970, this was originally the home of the Richard Feigen Gallery, and its arrival, in the shape of a transformed townhouse, signaled the emergence of the Upper East Side as a new center of the art world.

The building was extremely daring in its day, with a flattened, monolithic facade punctuated by elegantly punched windows. At ground level paired stainless steel pillars of the gi ant order dominated a shallow, loggia-like entranceway that led into one of the most stylish, streamlined interiors of the time. In due course, when the place proved to be impractical as an art gallery, it became a showcase for the Japanese fashion designer Hanae Mori.

Now, however, all of that is gone. Ms. Mori sold the building in 2002 to someone named Thomas Reynolds, and though Mr. Feigen and concerned neighbors raised complaints – and even appealed to the Landmarks Preservation Committee in June – it was too late. Those striking pillars have been removed and the loggia has been plugged with a strange, two-toned metal surface as clumsy as it is pointless. Clearly, it is time to start land marking more than just prewar buildings.

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At 135 E. 65th Street, at the northwest corner of Lexington Avenue, is a stately Georgian mansion made of red brick that has recently been transformed and is now looking for a renter. It is an appealing building and the restoration work has been carried out with some sensitivity. The only problem is the white marble cladding at ground level. The more you look at it, the more strangely it seems to fit in with the rest of the four-story building. The effect recalls that of someone who has just acquired a set of false teeth, blinding and unnatural in their gleaming whiteness, and who, out of misplaced vanity, simply cannot stop smiling.

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Throughout the city, steps have been taken to protect buildings, especially synagogues, that are likely to be potential targets of terrorism. For the most part, the resulting bulwarks are rather crude slabs of concrete whose intention is brutally apparent. At Trump Tower, however, they have done something a little better. Along the entire block from 56th Street to 57th on Fifth Avenue, the management has placed a squadron of granite planters, shaped like vaguely classical urns and filled with what I am told are yew trees.

As obstacles go, these appear to be impressively immovable, but they are also rather easy on the eye and look fully capable of performing their security functions to a superlative degree. This is what all of these security apparatus – which unfortunately proliferate in our city – should aspire to: the appearance of being there as an aesthetic statement, even when it is a utilitarian purpose that has called them into being. In the present instance, I am reminded of the motto of Michelangelo Buonarotti, Ex Forti Dulcedo: “Out of Strength came Beauty.”