Mrs Foster has a phobia and an obsession with being on time for everything. At the beginning of the story we learn that her husband has a penchant for the opposite: He likes to arrive late or leave two minutes late for most activities. The day they were leaving for the airport to visit her grandchildren, her husband (apparently quite on purpose) decided to join her at the driver's way too behind schedule. However, the flight got cancelled. After they return home to try and catch the flight again, we see that the husband again tried to slow things down by saying that he forgot his daughter's gift inside, which was in fact, in the car already. This is when she goes in to try to get him, and suddenly comes out to take the trip on her own ;)

Why is Mrs Foster upset with her husband at the beginning of "The Way Up To Heaven"?

The author begins by explaining that Mrs. Foster, a nervous, hypersensitive woman, has a phobia about being late.

All her life, Mrs. Foster had had an almost pathological fear of missing a train, a plane, a boat, or even a theatre curtain.

Her husband seems to take a secret sadistic pleasure in tormenting her by either deliberately making her late or at least keeping her anxious that she will be late. She doesn't know whether he does this deliberately. Part of his pleasure seems derived from her not knowing.

Mind you, it is by no means certain that this is what he did, yet whenever they were to go somewhere, his timing was so accurate--just a minute or two late, you understand--and his manner so bland that it was hard to believe he wasn't purposely inflicting a nasty private little torture of his own on the unhappy lady.

When the story opens, Mrs. Foster is planning to fly to Paris to spend six weeks with her daughter, son-in-law, and their children. It is a trip of the utmost importance to her, and, probably for this reason, her husband is tormenting her by dawdling and delaying their trip to the airport.

The six-storey house will be closed for the six weeks she will be in France. Mr. Foster will be staying at his club, and their servants will be furloughed for the entire six weeks. On this occasion the flight is delayed because of fog, and both Mr. and Mrs. Foster spend one more night in their home. The next morning, Mr. Foster dawdles again and makes it more and more likely that she will miss the plane. Just as they are finally about to leave, he tells he has to go back inside to look for a present he wanted her to take to the grandchildren in Paris, and he leaves her anxiously waiting in their chauffeur-driven limousine while he takes the elevator up to his bedroom.

Then, for the first time in their marriage, Mrs. Foster finds proof that her husband has been deliberately tormenting her by playing on her pathological fear of being late.

At this point, Mrs. Foster suddenly spotted a corner of something white wedged down in the crack of the seat on the side where her husband had been sitting. She reached over a pulled out a small paper-wrapped box, and at the same time she couldn't help noticing that it was wedged down firm and deep, as though with the help of a pushing hand.

Mrs. Foster races to the front door to tell her husband she has found the present--but then she hears something through the door that makes her stop, listen carefully, then remove the door-key and return to the limousine. She flies to Paris and spends happy six weeks with her beautiful grandchildren. She writes her husband regularly but does not hear from him because, as he tells her, he is not a letter-writer. When she returns to their New York home she has to make a phone call for a repair man. From the conversation, the reader understands that the elevator got stuck between the second and third floor and that Mr. Foster was imprisoned in it ever since she left to fly to Paris.

"The Way Up To Heaven" resembles Roald Dahl's story "A Lamb to the Slaughter" in several ways. Both Mrs. Maloney and Mrs. Foster are meek, submissive, long-suffering types who commit perfect crimes when they murder their husbands. Both have perfect alibis, but no one would ever suspect them of being capable of murder anyway. Both women might be said to be victims of mental cruelty. Both commit their crimes opportunistically and impulsively on the spur of the moment.