As for me,I have been trying to discover that 5% that cannot be done without microservices.
If I could trivially package them up and deploy them locally with intrinsically less effort and wall-time then the old way, that'd be amazing.
If I could somehow get the horizontal scaling promises and redundancy as some kind of built-in, like I can with say, memcache, that's be cool.
If I could do these kinds of "hard" things with them more trivially, that'd be really nice.
There's a lot of things I want them to do but it's a god-damn bull-riding rodeo every time I try to get there.
And before you reply, I know you're an expert and can do all these things trivially. That's amazing. The vast majority of the industry creates a giant fragile spaghetti knot with them and I am not a full time k8s admin nor do I want this to be a career trajectory. It should be like you know, wine, ffmpeg, imagemagick, virtualbox, lua, qemu, redis, gnuplot, lvm2, gdb, ssh, sqlite; tools like that. It's pretty easy to get them to do really nice things. Those things deliver on their promises and potential pretty nicely.
It's nice that nobody feels a need to hype curl or squid. They just work. Isn't that nice? I mean look at gdb's website: https://www.sourceware.org/gdb/ it doesn't even have CSS animations --- in fact, it doesn't even have CSS.
I still recall the day when my local Docker builds necessitated a new router to properly manage streaming traffic at home while I downloaded a few GBs of layer images. Or the time I wanted to setup a 'simple' hosted Kubernetes cluster of my own in my lab for testing, only to discover the nightmare that is networking on it. Then there was the grim discovery that Docker containers were much more sensitive to the hosting environment than I had assumed, resulting in some fun "but it worked and tested fine" moments.
Did they all work eventually for me? Yes. Was it simple? Not by my standards.
If you find all that simple, kudos to you.
Like, compared to implementing hitless rollback over bare metal services k8s way is "easy", just set some stuff in YAML and have proper healtchecks in your app.
I wish I had infinite time to document all the issues. This isn't a small nuanced detailed thing - it falls deeply, systemically fundamentally short and in practice you still get the magical monolithic system it tried to kill but now with more obfuscation, complexity and a theatrical slight of hand to convince yourself it isn't that.
Instead of the server being configured for the monolithic app, it's now extensively and carefully configured for the myriad of containers, hostnames, configurations and connections of the containers running the microservice app.
It's in practice the same problem with a different costume.
The other promise of it being a collection of smaller constrained services running on tcp ports talking to each other ... that's nothing new. You've invented the idea of computer networks.
But then for perfect decorrelation you'd also need independent databases behind the microservices, and queues between them for horizontal communication,and few are actually going all in with that, and so fall in the 95% where they go trough te motion and the effort of splitting microservices,but reap no actual benefit from it.