Timing !
The Sunshine Boys has to be one of my favourite comedies of all time and I agree with one of the posters on here who commented on the lack of discussion surrounding this marvellous work of genius. Matthau and Burns timing is of the highest calibre (like Lemmon and Matthau in The Odd Couple)and although I have watched many Neil Simon films (which I adore)I count the 2 films mentioned above as my favourites. It's almost like putting on a comfy pair of slippers and then watching some old friends !
Whenever you feel low, I suggest you put on the Sunshine Boys and feel that glow inside.............Ennnnttteeeerrr !
Jeff