1. Introduction 2. Detection of subsurface anomalies 3. Engineering judgement in field tests 4. Limitations of field tests 5. Project management without technical knowledge 6. Consequences of incomplete reporting 7. Reaching a conclusion in geotechnical failures 8. Ignoring site conditions in laboratory 9. Memory of excavated soil or rock 10. Project specific suitability of a strata 11. Overlooking the subsurface strata 12. Field recording of a geotechnical engineer 13. Interpretations of drilling data 14. Simulation of a site condition 15. Investigation steps in case of complex subsurface condition 16. Selecting suitable ground improvement method for a problematic site 17. Interpretation after a geotechnical failure 18. Excuses after a geotechnical failure 19. Interpretation of geotechnical reports 20. Interpretation without a conclusion