Ditto on the no text part. That is an accessibility failure that's way too widespread.
Sometimes I'm afraid to even push a button: does this delete my thing, or does it do some other irreversible change? Will I be able to tell what it did? Maybe it does something completely different, or maybe I'm lucky and it does in fact perform the action I'm looking for and which in my mind is a no-brainer to include?
And it's infected interpersonal communication too - people peppering their messages with emojis, even professional communications. It not only looks goofy, but is either redundant (when people just add the emoji together with the word it's meant to represent - such a bizarre practice) or, worse, ambiguous when the pictogram replaces the word and the recipient(s) can't make out what it depicts.
The most fun is when it's a mix - the message contains some emojis with accompanying translation, some without.
Bonus: good tests can also serve as technical documentation.
Though I have to disagree with the notion that documentation is as important or more so than code.
Documentation is certainly near the top of the list and often undervalued. I've worked on a project where documentation was lacking and it was painful to say the least.
Without documentation, changing or adding features can be a nightmare. Investigating bugs and offering support is also very difficult. But without code, you have nothing. No product, no users, no value.
There are (inferior) substitutes for documentation: specialized team knowledge, general technical expertise. These alternative pools of knowledge can be leveraged to create and improve documentation incrementally.
There's no replacement for the actual functionality of your applications.