[johnsmith1840]

Or their ulterior motive is that they don't have one and want to fit in? Meaning they would never diverge?

Didn't realize my point was so philisophical lol

[lucketone]

This is still an ulterior motive (even if benign; we all do it to some extent).

Behavior will diverge eventually.

Because emotions are what drives our decisions.

If you really love tennis, then you spend time and money on tennis. If you just say it to be nice (or to impress somebody), you will not invest into activity that much and will search for opportunity to stop.