I have been with Microsoft Excel, programming, playing, enhancing my life and teaching it for over 2 decades now.
I went from people loughing at me when I describe what I do, to challanging me, into admiring and respecting my work and finally paying me for what I do.
In this jeurney I learned how NOT to under estimate other peoples work.
That been said, I like to share other peoples work and websites. Here comes list if websites that can help you find your way into deep Excel