My “oh wow” moment was when I discovered Phalcon PHP framework (https://phalconphp.com/en/) about a year ago. I’ve switched all our projects on this framework and saved thousands of $$ because of the performance impact.
The other thing that made my day was when I discovered Django (https://www.djangoproject.com/). I never knew Python, but I decided to give it a try. The performance is amazing (I always thought that it was slower than PHP – I was wrong) and it seems I can build the projects faster that I ever could using PHP (with any framework).
What were your “wow” moments in your career? What was your best decision to improve your work?