The 3 things which have always resonated with me in particular have been:
1. The seemingly unsuccessful visit to John D. Rockefeller, which proved to be a blessing in disguise;
2. The Doctor's Opinions (how incredibly prescient these have proved to be); and
3. As a lawyer, I especially like the visit to AA No. 3, which is actually covered in 2 different places in the first 164 pages ("he walked out of that hospital a free man, never to drink again" - a "free man" indeed).