Skype for business is the biggest dumpster fire of software that I've had to use for work in the last few years. Truly awful- resource hog, screen sharing rarely works, and frequently crashes.
I'm glad I'm not alone in thinking this. Every little corner of the application seems to have a new UX failure or short coming that blows my mind.
Likewise, I'm amazed at how bad it is. Screen sharing issues, copy paste issues, lock ups (while everything else continues working fine), problems with not saving old messages properly, can't send messages because they are too long (really!?) ....on and on. Microsoft has been screwing up messengers for 20? years now - yes, I know different teams - and still, every new release or client is literally 1 step forward, 1 step back.