Skype is one of the very worst pieces of software I have ever used, the UI is so incredibly unintuitive it absolutely blows my mind.
Very early versions of the Mac Skype client (like 2.x or so) had a completely different UI layout that was multi-window and multitasking, and the program worked absurdly better back then.
Around version 5.x they started making mind-bogglingly stupid UI changes and I stubbornly held onto an old 2.x client just so I could keep the interface that was actually sensible.
So then, what does Microsoft do? They start screwing with the protocol itself and making everything refuse to work at all unless it is running the latest version. Then they introduce more ads and a generally scummier experience from one release to the next.
Even all of that was almost tolerable. Then they made a major "update" to the iOS client that must have removed about 50% of Skype's features for no apparent reason, and added annoyances or random breakages to whatever was left. Fortunately though, the release notes made it clear that they had flattened some buttons so we could all feel good about Skype's usefulness having been mostly obliterated.
Microsoft has, quite simply, ruined Skype. There is no more suitable word than that. It was a very promising protocol and the clients worked well, and Microsoft just completely destroyed it. It's honestly hard to believe the team is being paid to enhance Skype because it really does seem that the team is instead being given instructions to damage Skype in any way possible.