Who has got themselves into problems with unmanaged behaviour in ABAP restful model (RAP)? You might want to check out RAP - Unmanaged scenario.
ABAP Unit Framework and the related Test Knowledge is so fundamental for every serious ABAP Developer. A good overview in this Area for Beginners.
Having trouble how to send an Email with ABAP and using the OO-Way? Read this Article!
Algorithms and Fun -> this is impossible to combine? No, this little exercise shows this is possible.
Many of us are using open-source-project abap2xlsx. In this Blog, the Integration with the Google Sheet API is described thoroughly.