Why is it called a "Siddur"? Why not "Sefer Tefilla" or the like?
Siddur means order. The Tefillah MUST be said in a certain order. If things are said out of order, Kabbala teaches that it "twists up the pipes" [התהפכות היוצרות].
Mussar Haskel: You want things to change - daven. Don't only daven but daven in a SPECIFIC ORDER where there is a logical progression from one Tefilla to the next and one Bracha to the next [see Megilla 17b and 18a].
You want to make changes in your life? Make an ORDERLY PLAN how you are going to go about that. Don't make things hazy and up in the air. Plan your growth process carefully and methodically.
Like you daven with your siddur.
