In some cases the problem can be somewhat mitigated if the search is incremental (and fast), as it basically allows you to refine your regex in real time and he

In some cases the problem can be somewhat mitigated if the search is incremental (and fast), as it basically allows you to refine your regex in real time and help train the correct intuition. For example, you can type out "foo" at first which will, say, display 7 results, then when you add "()" you see the list shrunk by one, so you immediately know the regex missed one it's supposed to capture.