For me it's Rally (nee CA Agile Centra). It's dog slow, it has an interface cluttered with a million fields that we never use anymore (if we ever used them in the first place), but management loves it because they can generate a bunch of different reports from.
What's yours?
* Windows ==> macOS
* Jira ==> Trello
* Stash/Bitbucket ==> GitHub
* MS Office ==> Google Drive
* Box ==> Dropbox
* Outlook ==> Gmail
* Skype for Business ==> no chat system
In almost all of these cases, one person (or small group of people) made the purchasing decision for many more people. Likely this was based on price, not utility.
I consider myself lucky that I never have to use Internet Explorer ever. Some people have to use it every day.