Jira. It's slow. It's not intuitive. It's cluttered and hard to find anything in. It's easy to lose in progress work in it.

I can't think of a single piece of software that's stands out worse than the others but really it's anything that's still using Java or Flash of which there are a number of tools.

Probably Microsoft Teams but I know I'm lucky not to be using worse.

Adobe Creative Suite. Absolutely atrocious.

propel. it is the worst ive ever used.