This week WordPress project had started a trial of Slack web chat for communication, mostly replacing IRC. With influx of multiple hundreds of people the top complaint was soon the torrent of automated joining/leaving messages. Personally I was more irked about small font size of messages.
Almost immediately Stylish style was worked out to hide unwanted messages and shared for others to use. I created my own style to bump font size.
This is how Stylish is often the crutch for missing flexibility in web.
What it does
Cascading Style Sheets give the web limitless amount of presentation options. As web grew towards less and less simple pages a lot of attention was paid to design, but much less so went towards level of individual flexibility.
Web applications are commonly lacking in flexible (or any at all) customization options, that desktop software (especially text–centric) considers a norm.
Stylish is a browser extension enabling end–users to add CSS to the sites, as well as share their customizations.
The strength of Stylish is same as its formula — apply any CSS to any site, giving same limitless flexibility in adjustments as the one that empowered the original sites to be created.
The additional rules can be targeted very precisely to URLs, impacting specific sites and even different sections of same site in different ways.
Styles can be shared online, installed, and kept updated.
The official extensions is for Chrome and Firefox, but quite a few unofficial ports exist for other browsers. I use one for old Opera the most.
Just as writing CSS is powerful, it's hardly trivial. Using Stylish for creating own customizations demands knowledge of CSS and quickly escalates demand to much more than basic levels for impacting elaborate sites.
While online catalog is convenient (and skips writing CSS part) I found most items there too commonly be a little too drastic, heavily remodeling sites they apply to. It seems to be more of playground for people enjoying sharp turns, rather than subtle adjustments.
Stylish is a total must have (and must use) for anyone with CSS knowledge. Outside of that group your mileage may vary.
I hardly feel a pull to customize every single site with it, but when I need to — it's amazingly useful.