I have rarely heard of any living person who took this promise seriously. In general it is the custom either to ignore the commandments of the Torah or to add to them.Few people think that the Torah provides all the answers to human problems.
Some famous examples of commandments that are added to the Torah are commandment to believe in supposedly righteous people. Some people add the idea of believing in one person and they also the idea of adding mitzvahs and as many rituals as possible. In any case there is no indication in the Torah that believing in any person is a requirement for "life and the good."
In the Torah, no human is a god.
In the Torah we do not find a requirement to go to therapy to merit to "The Life and the Good". Rather in terms the difficulties we find in human affairs we find a well worked out world view in the Torah that psychology is different from.
The world view of the Torah is in fact very different from most modern viewpoints.
[The Torah does not claim it was written by God. But it does claim a message from God. Do these commandments and you will proper. Don't do them and you will regret it.]