It's with so many things! Some evergreens just from last week here on HN:
- Rails is horribly slow!
- Python is still stuck migrating to Python 3!
- MySQL doesn't scale!
- Haskell tooling sucks!
- io_uring is insecure!
- ... and dozens more just in the programming world. These are just off the top of my head. Probably hundreds more in the wider engineering world.