A little prep work goes a long way

Preparations are always needed for any kind of trips, I guess everyone can agree on this. While snags happens, and things went south, prep work would provide something to fall back to.
Yet, most of the time most people don’t prepare enough. I am no exception. Like the time I didn’t go for a site visit on the course of this year’s Kyoto Marathon, and a particular slope at 39km almost kicked me out of the race. Or that Monday, when I was in Kurashiki to visit Ohara Museum of Art, and found that it closes on Mondays.
Or that one time at Moji. I was there to visit the Kanmon Straits, and Shunpanro in Shimonoseki, the first modern restaurant in Japan to serve the poisonous Fugu fish safely (it was also the negotiation site for the aftermath of First Sino-Japanese War). I thought the ryokan I booked online was a bargain, 5000 yen for the night with a tatami room. Little do I know that it was a dingy frat house like place, with a run-down cafe downstairs. A look at the dark, dank room and I knew it’s gonna be tough to stay. By the time I almost stomped through the flimsy tatami floor, enough was enough. I sneaked out of the place with my stuff, leaving the key inside the room, since I already paid my rent during booking (a win to offset the situation). Luckily, there was a western style hotel in the neighborhood, and I got a room.
Afterwards, I went back to Jalan (where I booked the ryokan) for a bit of checking. Among the comments, users mentioned the place as for short term laborers. That explained why it wasn’t traveler-graded. Had I found those comments when I booked, I would have saved the extra I need to pay for the hotel. Lesson learned: read the comments, and keep both eyes open when the “bargain” is too good to be true.
Now, do you have a story of yours, when your Japan trip(s) didn’t went according to plans? What did you do to keep things going? Let’s discuss!