What about Showa makes it your favorite era?

[Showa Gyaos]

It was an era when the filmmakers weren't afraid to explore, to try new things. The craziest things happened in the Showa series, the likes of which we'll never experience again. That is what makes it my favorite era.

[The Robber]

I love the shows era for its color and saturations of the films. Colors just pop.

Maybe it's weird of me, but this is a big part of why I like it. It's just got this glow to it.

[Missingno.]

I think the first half of the Showa era was the best. I believe that after War of the Gargantuas where the series started to enter its downfall, with only a few good exceptions here and there, such as king Kong Escapes, DaM, Space Amoeba, Godzilla vs. Megalon, Submersion of Japan, Godzilla vs. MechaGodzilla, Prophecies of Nostradamus, and Terror of MechaGodzilla (not sure why everyone bashes on this one). The biggest reason I like the first half is because of the fact that there was other monster films besides Godzilla. There was Rodan, The Mysterians, Dogora, Mothra, and The Last War to name a few, giving the Showa series much more variety than any other film era to come from Toho.

[imperious reptilius]

Like everyone else said, Showa knew what it was and took pride in it. Even the worst of it had a sort of strange sincere charm to it.

Not to mention the very best are classics; not only to the genre but to cinema in general.

[Rodanguirus]

It's been covered, but I love how multiple kaiju actually get to put in multiple appearances, and the various creatures and alignments become well known to the people of this world. It was compared earlier to a universe of superheroes and villains, with the added appeal of being giant monsters. I also love that it gives me so many opportunities to root for Godzilla/monsters in general.

[Fighing On Fuji]

The biggest thing about the Showa series that I will always love is that it felt DIRTY. Literal dirt. The images were grainy, and the colors were muted in comparison to the Heisei especially. They didn't throw this anime-inspired nonsense at you like they did with FW and the Kiryu movies, they didn't take ridiculous situations overly seriously like GMK (and when they did it felt pleasantly corny instead of uncomfortably cringeworthy), they didn't shoehorn a bunch of saccharine sentimentality like they did with every Heisei movie from Mothra onwards, and they had brutal, down-to-earth human fight scenes.
There's a reason why my favorite post-Showa Godzilla movie is G2K. Yes, it stumbles into a couple of the traps I mentioned, but that lingering Showa-esque sincerity keeps it bearable.

[Kaiju.unlimited]

i think the best thing about is they could do any weird thing they wanted to in the films and no one would ever question it!