Not as good as You've Got Mail, in my opinion, but since it's the inspiration behind it, it's great. It's still very impressive to see Jimmy Stewart's character change and realize the person he really fell in love with and get over his unfounded prejudices.
Stewart really had to humble himself and put aside the things he saw in Margaret Sullivan that seemed to bug him. In marriage, I think it is important to realize what drew you into the person initially; like they say, "keep your eyes wide open during courtship [to make sure you don't overlook anything important] and half shut after marriage [being forgiving of the other persons faults]." I think that's the message I found that moved me the most.
Mr. Matuchek's lack of communication with his employees displayed another poignant lesson. It is important to be open and honest in all situation before jumping to any conclusions. You must strive to assume the best in people and try to understand as much of a situation as you can. I imagine it could be very difficult in a situation like he found himself with in the movie, losing his trust in his wife.
Back to the love story, so many times people get misled by their emotions and fail to see (or choose not to see) the shortcomings of their sweetheart. Sometimes more than just shortcomings are overlooked for the sense of belonging or being loved. It's important to view the counterpart of the relationship in an everyday setting, how they react in different situations and with different types of people. James Stewart is able to do that with Margaret Sullivan and he's willing to accept her as she is, knowing that she is capable of loving him. And of course everything works out in the end, a bit abrupt though if I might add. Meg Ryan's falling in love with Tom Hanks because of his genuine kindness was better displayed in You've Got Mail. I'll have to see In the Good Ol' Summertime again to comment on that version.