Great topic, Pablo!
Here are many of the challenges I've faced over the years of building automated testing.
1) Creating & supporting your test environment(s).
2) To go along with your 3rd question, Will a failure of the automated tests ever stop a release?
3) How do you get others to contribute to the automation test framework and coverage?
4) How do you make the reporting of the success/failure of the automated tests publicly consumable?
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