a possible answer by a non-observing person could be "I just do it, bro",
and a possible answer by an observing person also could be "I just do it, bro".
Although the possible answers are the same, there are two differences in terms of motivation that can be addressed.
One is in terms of degree of disclosure.
On one hand, the non-observing person is being fully honest on expressing his lack of rationale (all out). On the other hand, the observing person would say that to avoid being boastful by explaining his intrinsic motivation (partially out).
Second is in terms of an attempt to be concise in speech.
In this case, the non-observing person would say that when he means, "i just do it because everyone is doing it" while the observing person would say that when he means, "i just do it because in my knowledge, it pleases Him".