I think I'd have to go with Mr. Rogers' Neighborhood.
My initial reaction was "TWIN PEAKS" (and i shouted it in my head) but, as good of a show as that is, I think it would leave me dwelling on the sinister undercurrents of the human condition and the occult which I already do enough of.
Mr. Rogers Neighborhood is a legitimately awesome show and celebrates the good in human nature, interpersonal relationships and imagination.