good god Skype sucked so bad. the interface was awful, the program was super bloated, the Linux and OSX versions were barely supported, the mobile version was unusable, the audio quality was super fucking crusty, it crashed all the time. I could go on. good riddance.
EDIT: y'know what else I really, really don't miss? fucking Steam Chat. while it was definitely more stable than Skype, it was still clunky as hell and often just Didn't Fucking Work for No Goddamn Reason.