I didn't have a documented birth plan. I went private and had an OB that I trusted as well as a hospital I felt comfortable in. DH knew that I wanted to avoid an epi if possible and that I wanted to use water as pain relief. I lasted 5min in the bath before it got too painful lol! Then had an epi after being only 3cm after 12hrs of intense contractions 2min apart. I also has an episiotomy and forceps delivery.
I think that for me, not having a strict plan meant that I had nothing to measure myself against so I never felt like I failed or anything like that. I know it's different for others but I know my own mind and taking it as it comes means I make better decisions for myself based on actual circumstance rather than preconceived ideas.