I was a back-end & full-stack guy for some time, doing things from ETL stuff to pipe-lining more colorful things interfacing with things from search, other analysis, etc... I started doing more "real" software development midway into college and was lucky (or maybe unlucky) enough to be able to develop my skills with a pretty full-stack spectrum (now doing things with Dart, React, to Python, Java, Docker, ES, Reddis, Helm, Jenkins, K8, AWS/GCP, etc, etc...).

I love Java (literally the best). Django is easy. Go is alright. jQuery & Bootstrap are great. Moving into heavy UI i.e, React/Redux, the entire JS ecosystem, mobile fragmentation, absurd, pointless policy changes in the UI world are absolutely 10x more annoying, difficult, arbitrary, meaningless, buggy, and horrible than anything back-end. TensorFlow, Unstructured-Data, NoSQL, CI/CD? No problem. You have an API, documentation that works, Linux systems that are consistent, predictable, repeatable. UI/UX? Changes every day. Docs from 2 years ago often don't work. Lower barrier to entry, lower quality ecosystem. Security & supply-chain nightmare. Fragmentation for no reason other than large corporations focusing on bottom lines and leaking core-rot. It's a insult to time investment.

I can build a full-stack, horizontally scalable, complex, awesome system with whatever tools you want I can guarantee you that no matter what you throw at me, I'll spend prob 75% screwing around with JS bugs, mobile garbage, awful ecosystems, and pointless garbage that at the end of the day comes down to nitpicking about pixel performance and arbitrary platforms.

I know I'm not the only who's wasted countless hours of my own time, clients money, companies time, and real-end-user money and value on things that were shiny and interesting to a PM or UX team and ended up sinking over half the cost of project on effectively nothing. The people that make the decisions don't understand it, because UI/UX is literally all they can "see". It's insanity. If I ever start a company, I'd love to model it off a concept like Stripe; such a beautiful concept of a beautiful idea run by some of the smartest guys out there, all based entirely off an API. No play-store policies, shifting trends, corporate politics, useless garbage, pure JS developers maintaining random repo's for tools that don't need to be built.

If you're smart, be like Amazon, Google, Facebook and every other huge idea: Make an unresponsive, useful front-end and just say no to fancy UI. Amazons website is an glorious defiance to the quite frankly disgusting culture of what robs real engineers time and resources away from something like curing disease, balancing equality, providing security, and focusing on things that could actually make the world a better place. Look at this site right here. Look what happened to Reddit.

If it's more than Bootstrap and you're not funded, just say no to UI/UX. JUST SAY NO.

EDIT: There's probably some good takeaways from the book "Zen and the Art of Motorcycle Maintenance". Do yourself and the world a favor by not feeding this economy of engineered over-complexity and willful-ignorance, especially in this day in age. Our species might be about to go extinct. There's more important things to do. Seriously.