Most 'Twilight Zone' episodes that I remember fondly are suspenseful and ironic, ending with a twist that makes you hate the darker side of humanity... but 'In Praise of Pip' isn't like that. Nor is it sappy. Just a beautiful, thoughtful episode that you can watch as many times as 'To Serve Mankind' or 'Eye of the Beholder', etc. and still it always affects you. Jack Klugman is so perfect in this role, that you love, hate, and sympasize with him all at the same time. People have written stories and songs on the subject of parental neglect but to its benefit, 'Pip' went a step further. Depicting not only a father "not being there" for his son but also the love he wishes he could have expressed and his self-hate for having missed so many oppurtunities.
I'm glad that 'The Twilight Zone' was so flexible that it understood that a 'twist ending' can be as simple as showing the 'good' in every human being.