Both are "feel good" mini dramas. In To. Jenny ML teaches FL how to play guitar, whereas in Understanding of dance ML teaches FL how to dance without being embarrassed.
Really cute dramas, both of them.

Both series talk about time travel and how it works as a way for ML to become a better person.
Funny "fish out of water" moments and sequences due to the new world that ML is discovering.
Both MLs are sometimes goofy, childish and clumsy, sometimes serious and mature. Both have a somber side too and have a great evolution.
SML has been a friend of FL since childhood.
The main couple have many swoon worthy moments in both series.
Both series talk about health problems of the elderly.