Completely random example, notice the 'limit':
IMO, the only reason why java is still in use - superb IDE and tooling, that compensate terrible language design.
Poor language design (undecideable edge cases, dynamic and unpredictable meanings) makes it impossible to create a satisfying IDE experience.
If you're using vim or emacs to write code, you're wasting your employer's time. A good IDE makes you more productive.
Vertical alignment. When you press the down arrow, you don't know what position your cursor will land on because it's not visually aligned with the character above. Kind of defeats the purpose of a monospace font (within that one line where it's applied).