As soon as you recognise the word 'just' is problematic it can be very useful. As in, 'why don't you just'.

If you find yourself about to say 'just', it's a great time to pause and think about why the person hasn't 'just' done what you're about to suggest. It usually gives a deeper insight into the problem - usually (but not always) it's a harder problem than it initially looks.

And even if the solution really is obvious, it's often useful to think about why it wasn't obvious to the other person.