I think I’ve something to add to the above.
Its true and not too that we can not laugh at same joke again and again. At the same time its true and not too that we keep crying over same thing again and again.
We may not laugh over the same joke again and again but when the same joke is recollected after sometime, we often laugh almost matching to the extent we had it first time or we may laugh further more than anytime!
We may cry at same thing again and again when it is recollected after an interval, but we do not cry about it continuously. Although, we cry at same thing, we do not cry with the same intensity with which we had cried for the first time, or we may cry further more than anytime!
It all depends on how much we do want the fun to happen and the misery not to, again and again!
The bottom line is we do cry and laugh again and again, on same thing, of course with a change in the intensity of the emotions.