Today I explained special relativity to my eldest daughter.
At her age (12 years old) I was struggling to understand it by myself, because nobody was able to explain it to me.
It took 2-3 year to really understand it despite reading anything I could about it: I remember the day when I was trying to explain what I did understand about it to a schoolmate and pieces finally went all in place.
Now she grasped the implications of c as a constant despite the reference system in roughly an hour.
Her smile was... amazing.
I feel so proud...
(I had to tell this to someone)