Most ERP systems are big and complex due to the integrated nature of all the modules.  A simple change in the inventory management system can have huge impact on financials (ie how perpetual inventory is valued).  Therefore you need to have a whole team of SAP "experts" setup and configure your system to make one module work the way you want it to without adversely affecting other modules.  Sometimes the "experts" are knowledgeable, sometimes not, but that really isn't SAP's fault (unless you contract them directly from SAP).  SAP isn't alone in the integration vs ease of implementation continuum. SAP does have a horrible interface.  I'd rank it slightly better than Lotus Notes.  It is ugly and non-intuitive.  I was really hoping Microsoft would buy them out and make the interface somewhat usable.  Its development language ABAP is also horrible - it looks like some bastardized version of COBOL.  I was looking at some program last week that drops a 25 line text file out for barcoded production labels.  About 500 characters total output and maybe 20 fields - the program was no less than 1400 lines of code.  Something I could do in .Net in 50 lines max.As far as customizing your business to fit SAP, sometimes that is the smartest thing to do.  The absolutely worst thing you can do is customize SAP.  If your business process and SAP don't mesh, do not under any circumstance change core SAP code.  Write an external system that interfaces with SAP via standard import processes, EDI or some other service.  Customizing core code will just cause problems with patches / upgrades.The big advantage of SAP and other ERP systems is that they are integrated.  If you setup and configure the modules correctly, you don't have to worry about consolidating data from disparate systems into Excel to do financial reporting, sales forecasting, etc.  It just takes a lot of time and money to get there and most companies don't consider all the costs associated with implementing an ERP system.