Glitch

Why is it when you think you know what you are doing and things seem like they are working out all of a sudden there is a glitch. I don't know what it is.  People tell you what your supposed to do but somehow they don't give you all the information and your just supposed to know. Why can't people give you step by step information? Or like a FAQ sheet, if this happens do this or if that happens do that.   Is that too much to ask?

I know this doesn't make sense LOL but I just had to get this out.