I remember reading three things about these men (LBJ and Nixon) who became president. First, neither man liked the other in reference to LBJ and Nixon. Nixon was always afraid LBJ would send him through a wall.
Second, LBJ liked a powerful shower in the morning. He had the water pressure in the WH living quarters set to full psi and that water pressure nearly knocked Nixon on his duff the first time he used it. Nixon got the water pressure readjusted.
Last, LBJ left a personal note in his own handwriting for Nixon. Paraphrased it read in part: Dick, Congratulations on becoming President. It is the most important, yet nerve wracking job anyone can ever have. I can tell you that you are doing this job right if half the country hates your guts at any given time. It is lonely. It is just you at the end of the day, hoping any of your decisions are setting the right course.
If you ever need to talk, call me. I promise to listen. I won't judge, cuss, or gripe. Lyndon
Source: Robert Mallinger (Quora)