Hello Telly, great article - really makes you think! Thanks for sharing.
I would say that the purpose of life is to strive for goodness, or should I say, grow into goodness/love ("you must accordingly be perfect as your heavenly Father is perfect"). There's a kind of spark in every single person (who hasn't snuffed it out through constant pursuit of evil) which seeks to express itself in some form or another. Your mentor Philip merely exploited (in a perfectly reasonable way) this human trait. That "feeling" inside every person is itching to get out if it's allowed (if one "becomes like this child to enter the kingdom of God"), and when another person draws attention to it, it is received with joy. This faith in love that people have (but cannot put words to it) is what makes life worthwhile; every path a person takes for a higher purpose will be something related to a loving expression.
Regarding the statement "people want to hear good things about themselves"; it's not so much about just the ego/pride - in a spiritual sense, to be cognisant of one's morality can and should result in a healthy amount of self respect....which in turn will lead to more of these positive (selfless) behaviours. Ironically, to be proud of something you've achieved in a spiritual sense will not lead to being puffed up, rather, it will help one to continue the path. Another person bringing attention to it helps to bring clarity to this all important mission of life (i.e.to grow in love, to really know Jehovah).
Why do people want to become JWs? Many reasons obviously, but one of the basic ones - in life you are only truly "living" when you are growing - becoming better than you were yesterday. Living the Truth entails challenges, it entails constant reminders of one's religious duties (or more accurately, privileges) etc....thus rather than shrinking back to a life of mediocrity, it encourages the character to develop (not stand still). To stand out as different in a world where you are constantly told to "not be hard on yourself" appeals to those who don't want to just settle for average. Life is not about settling, it's a constant "playground" of activity and life lessons. To neglect one's spiritual need is like running out of gas (or petrol as we say in Scotland lol). Spirituality is about growth, constant change and development/improvement (whereby you benefit those around you) - it is that which brings real satisfaction/joy.