To cut it with the programme, one must have a certain amount of guts. The process is not exactly pleasant.
'Almost none of us liked the self-searching, the levelling of our pride, the confession of shortcomings which the process requires for its successful consummation.' (Big Book)
'Instincts on rampage balk at investigation. The minute we make a serious attempt to probe them, we are liable to suffer severe reactions.' (Twelve Steps and Twelve Traditions)
When entering the Step Four (and Step Eight) process, it is wise to be prepared for this. You will hate your sponsor, you will hate the process. You will defend yourself, you will abase yourself so grotesquely that no truth can be seen, you will skate over the surface producing just enough to give the appearance of true inventory, or you will avoid the process altogether.
The only way through is through, and this requires doing the job maximally diligently, facing the facts without balking, and siding with your higher self over the ego's thrashing.
Unfortunately, a lot of people drop out of the process because they are unwilling to do this.