As with any task carried out in the ArcGIS software suite, data is the foundation. The old saying of “Garbage in Garbage out” still applies. Data, whether it is in a text format or geographic (shapefile or File Geodatabase Feature class) will impact on the behaviour, use and display of data in ArcGIS.
I do have one proviso in this situation and that is that I’ve given up on perfection. Deviation from the real world is expected. Distortions from the coordinate system chosen, method of capture and scale are some of the sources of error in geographic data. What is important is what error is acceptable for the task you are carrying out.