Sometimes when I see the design of a UI vs. what it actually looks like, it reminds me of a Tinder date where you realize the person's pictures are from 10 - 15 years ago and now you think you're on a date with their grandparent. Or that drunken club makeout and then you go on a date the following weekend in broad daylight and you wish you didn't. Do you get the picture?
Going for pixel perfection is like going for perfection in anything. It's difficult. Many developers seem to give up before they even start.
I find satisfaction in going for perfection though. Sometimes I'll struggle trying to achieve a design that I later learned is impossible. In that case the design needs to be adjusted. But I learned a lot and pushed the limits in that moment.
It's rare when I get to start an app from scratch. The last time this happened, I was the only front end developer. That meant my name was going to be tide to what this website looked like. The design was beautiful. It made all other enterprise apps look horrific. So I wanted to do the design justice.
After about a month of working, the PM saw the first version of the site. She said, "wow it looks just like the designs." It made me feel so good to hear that. But... shouldn't it always look just like the designs? Isn't that what the client has paid for?
I think I've learned the most in anything I've tried by working to get the job done right. It's easy to get broad strokes right. But when it gets down to the details, you start going into unknown territory. In my case, it also tests my mental toughness. Towards the end of a task, I'll feel myself getting lazy, cutting corners and just wanting it to end.
I think if you strive for pixel perfect layouts, it'll be worth the trouble. From my experience it seems to be a rare skill these days, so you'll set yourself apart from the competition.
Software developers don't strive to learn more about UI design, layout, html, css. They're seen as basic tools and something to get just the gist of, yet I've seen few people who are really good at them.
The two people I know at my company who are good at this are treasures. I go to them, I ask them questions. I try my best to stay in good standing with them. If they left the company, it would suck.