Why are there days that make you sentimental and teary eyed?

Today is one of these days and so this blog is truly an elderly blue. Along the way, our hope is it gets solved  and becomes elderly blow. So here goes: Why are their days that seem to make one sentimental consequently teary eyed?
One possible reason is because once you reach your 50's, 60's and upward, it is conducive to "looking inward" and in hind sight deeply ask  how life has been and where to from here to there? This leads you to the next level ergo:
Two: You look at the loved ones around you and smile: life is just fine.
Three: You notice that the years passed by without you minding so much the regular separation and coming home either by the children or the inevitable seminar here here and there that come with the job.
Four: From here on, the mood is one which makes you focus on the good times and the bad times that your family has overcome - now one by one the children have decided to make a life for themselves. Will this be the case for every one of them?
Five: This is the moment when you become sentimental and teary eyed. In our case, the whole day was tinged with such "lump" in the heart that simple conversations are bound to be "tear jerk". 
This portion encouraged us to visit some sites and out there, many shared their sentimental days, their poems, their thoughts - ah, life must go on, sentimental or not.

Why are there days that make you sentimental and teary eyed? - because life is better this way. You treasure the days and all the pains are pains no more but "spices" that make you go on hoping there are better days for every one.
Our beloved dog, Michael 2 witnessed all our pains just as Michael 1 did. Stay with us Michael. . .