If I were to pick one web development pet peeve, it would be the lack of accessibility on websites. And not just that, but specifically the lack of regard people have for the subject.
Note: For those unfamiliar with the subject: in both "real life" and on the internet there are many people with some form of disability. Blindness and deafness are well-known limiting factors on the web, but they're rarely dealt with appropriately. Many websites use poor quality HTML, which renders them unusable for screen readers, or videos lack captions, so deaf people can't hear them.
I'm going to spare you the technical details on how to achieve a11y, which is how the term is aptly abbreviated. I'm building a list of developers who tweet about accessibility on Twitter, which is always short of new additions, and which you can refer to (aside from your usual search engine). Make sure to check their resources for more information.
Back to the pet peeve thing. A proper front-end web developer builds semantically correct HTML by default. Proper HTML is the base of any accessible website, and adding some extra help tags is usually not much work. Before a front-end developer starts, UX and UI designers should also have had the subject in mind.
So why do people use the age-old "it's too expensive" excuse to avoid even having to think about a11y? If someone in a wheelchair tries to enter your house, do you ignore them? If you see a door is about to hit a blind person who can't see it coming, do you let it hit them in the face? If the answer to this is yes: you're an asshole; if the answer is no: then why would you allow this behavior on the internet?
Also, well-built websites do not only help people with disabilities: search engines value these websites more than lesser quality sites. Also, crawlers and other indexing services perform better on them. Since the prime goal of a website should be to convey information, this is all a good thing.
The melting pot that is the internet
Web developers tend to build sites for people with 20/20 vision, good hearing, fast internet, proper smartphones or computers, and a good understanding of the internet. These people are our ideal target audience, but they're only a small part of our user base.
The pool of internet users is a melting pot like any other, although probably not in the way you're thinking now. The next time you're thinking about buying or developing a website, think about:
People with damaged senses:
- complete deafness
- bad hearing
- complete blindness
- bad sight
- color blindness
People who are physically limited:
- lacking one (functional) arm
- having no (functional) arms at all
- limited turning radius of the neck
- limited movement radius of the upper body
People with learning difficulties, or (neurological) disorders:
- dyslexia
- dyscalculia
- epilepsy
- high sensitivity
- dizziness / other issues when looking at a screen for a prolonged time
Cultural or environmental differences:
- people used to reading text right-to-left, instead of industry standard left-to-right
- people in an area where sounds are forbidden (e.g., library)
- slow internet, or bad computer hardware
- lack of tech-savviness from the user
…and these are just the issues I could come up within a few minutes. I'm sure you've found at least one point in the list that applies to someone you know (especially when you know older people).
I'd like to leave you with an assignment: next time someone argues about the monetary cost of accessibility, think about the people you know. Ask yourself whether saving money is an acceptable reason to exclude people from reaching information on the internet.
I sincerely hope that your answer to the question is "no".
Afterword
There are many ways people consume content. Hardly everyone is the perfect user. Stick up for those who are not. Do not exclude people.