Not sure if it's been noticed or mentioned here yet or not, not sure what to search for to find it if it were, but in reading the walkthrough about Penny's favor system, I noticed that you can dig yourself into a hole.
It says if you run out of seeds you need to talk to her during dinner to get more, but having dinner takes 4 favor.
If you are out of seeds, have nothing planted, have plowed every tile, and run out of favor, you can't have dinner, can't get more seeds, and can't get more favor, thus locking you out of doing anything further with her.
We should probably be able to ask her for seeds while she's out in the field, thus letting us get more even when we're out of favor and preventing this dead-end. Or just remove the favor system, either or.
Of course, this could have already been fixed and just not noted in the walkthrough, as I said, I'm not sure what to put in the search box to try to find out, and I'm not digging through 145 pages manually, so do let me know if that's the case.
Just a thought I had.