[Kenji]

Skype. Everyone has it and it's so bad. Random freezes of the conversation or the window, call drops (Teamspeak has almost none), can't disable alerts for file transfers in a group chat, the search doesn't work properly (can't find words that are there) in a long chat log. I could go on. I have used many chat clients in my life, but I have never seen such a bad implementation before. It is a mystery to me why everyone uses it, thus forcing me to use it too.

[jonnathanson]

People use it because it's still a lot more well known, convenient, and ubiquitous than the alternatives (although that isn't saying much). I prefer Google Hangouts myself, but a lot of people I deal with are familiar with Skype, and don't seem to want to switch over.

[matthewmacleod]

I'd extend this to videoconferencing and remote meeting solutions in general. I've never found anything that works reliable, across platforms, with a simple interface, can scale to larger events, and so on. You'd think it would be a solved problem by now.

[maaaats]

When talking with a remote clients/offices, we've found http://appear.in/ to be great. No hassle with adding each other on Skype/Google, just send a link. Even supports screen sharing when demoing. Not saying it will be a silver bullet for your listed issues, though.