system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Why Internet Explorer is (supposedly) so "horrible".
gpt
The internet has a set of standards for people writing websites. The languages they use (HTML, javascript, whatever) have well defined rules that are agreed on and set by a central body. This means that anyone can write a program (a web browser) to receive a website and interpret the code following those rules.

Unfortunately, IE broke those rules in a big way, and still does, though it's much better thanks to the competition of recent years. This was originally simply a nasty business practice of value to MS. By breaking the rules, they forced everyone who wanted their sites to work in IE to break the rules when writing their code. This meant that they had to write lots of things twice, once for IE, and once for anyone else that wanted to see them, but that took much longer so many people just wrote it once for IE. This pushed out IEs competitors because websites simply didn't work for them any more.

Over time, IE became the dominant browser, through a combination of easily reaching many users by being preinstalled in windows, and by the above deliberate standards breaking. At this point, it promptly stopped innovating and everything simply stagnated for several years before firefox came along with tabbed browsing and other new things that made things competitive again. During and after those years, IE continued to make things difficult, with its inconsistent, non-standard and poorly documented behaviour that website designers had to work around.

This all leads to a range of reasons that people don't like IE:

* It's hard to write websites to work in it, because it deliberately broke standards in order to try and be anticompetitive.
* It's often lagged behind supporting new things, or tried to break those standards as well, making everyones web experience less good.
* It's simply less powerful and featureful than its competitors. This is becoming less true, but it has been for many years. For instance, when firefox first appeared, it included revolutionary things like tabbed browsing that IE hadn't come up with in *years* of internet dominance.

Again, this is all less true than it used to be, but IE carries an enduring legacy of hate because of just how incredibly it messed things up for everyone. To put things in perspective, IE attained complete market dominance somewhere around 2002, and began losing significant amounts around 2006-2007. Between those dates, around 4 years, almost *nothing* changed and the only way people used the internet was IE which was objectively poor. Now, look at how much things have changed in the last 4 years, how many more things your browser can do, and how fast it is now! Even changes in the internet itself, new technologies like google docs and facebook chat, are partly driven by the capabilities of the browsers that have to display them. Imagine using the internet from 4 years ago, and *then* you can see just how much IE crippled things, and understand one of the big reasons people dislike it. And that's without even looking at the reasons IEs technical backend was terrible.