Walter and Ruth Younger face a number of different pressures in their marriage, however the most important strain is that of the inexorable grind of poverty and how this does not match Walter's dream for himself and his family. Both Walter and Ruth have to work very hard every day just to merely make ends meet. Ruth is very pragmatic about this, and clearly this approach helps her to cope with the various setbacks and problems they face. Walter, however, always has a dream of being able to gain wealth and find some way of becoming more affluent. Note what he says to Travis:
You wouldn’t understand yet, son, but your daddy’s gonna make a transaction... a business transaction that’s going to change our lives... That’s how come one day when you ‘bout seventeen years old I’ll come home... I’ll pull the car up on the driveway... just a plain black Chrysler, I think, with white walls—no—black tires... the gardener will be clipping away at the hedges and he’ll say, “Good evening, Mr. Younger.” And I’ll say, “Hello, Jefferson, how are you this evening?”
Walter dreams of a world were he can enjoy the same kind of material prosperity that he sees whites enjoying all around him. This is of course something that creates significant tension, especially when Mama receives the life insurance money and Walter tries to get Ruth to help him persuade Mama to give him the money so he can set up a liquor business. It is Walter's dream based in the context of unrelenting poverty of the Younger family that therefore is the biggest tension.