It's slow to start, constantly downloads a bazillion updates. Information-wise, it's not very dense. It's hard to customize; doing so requires a bunch of hacky stuff: https://github.com/AryToNeX/Glasscord/wiki/Installation
Using a third-party client is a bannable offense under the terms of service. I hate the little "emoticon" icons that are all over the place. It set itself to auto-start on boot (this behavior may be different on win/mac). I don't like trusting it with my messages. It tries to show what applications users are running at the moment. There have been some improvements, but I still don't trust the security of electron.
These are some of the ones I can remember off the top of my head. Generally, it always seemed like it was both trying to baby me and seem "cool". It's many of the things I hate in modern software in one application. It's a chat app, which should shut up and show me messages, not try to double as a social network. It's also a voice conferencing app, which should shut up and transmit/receive audio, not try to double as a social network.
I know a lot of other people who seem to like it as well; good for y'all. All of this would be much less offensive if it hadn't banned me for opting out of its webshit.
I'm going to assume you ask this question because you're honestly curious about GP's discontent with Discord's interface, so this is NOT directed at you, but ...
One of the things I've often noticed is that people like to shame me for being discontent with e.g. WeChat's interface or Facebook's interface. "What's wrong with it? I think it's great! [... and you're weird]" and that mentality of casting away hacker types who want to invent their own UIs is extremely toxic to creativity and innovation, but it's a pattern I've seen happen very frequently with all of these walled-garden apps. (Again this is not directed at you)
Yes, I totally agree with that being a problem. At the end of the day different UIs satisfy the goals of different people. It's a bit pointless to bash people for picking things that fit their lifestyle.
