These thoughts advance the conversation and our understanding of helpfulness and service. But the criteria for helpfulness cannot be solely the response of the helpee. Consider the numerous situations where "you'll thank me later". David Ryan seems to recognize this in the reference to children or dementia sufferers. But the same idea applies to all of us in one area or another in which we have our own blind spots and incompetencies. Thus, as David suggests, 'helpfulness' is much more complicated than it at first appears.
On Aug 8, 2013 Wayne Iba wrote on Serving Is Different From Helping And Fixing, by Rachel Naomi Remen:
Indeed, we need more reflection on the nature of helpfulness and service such as Rachel Remen's article represents. While the distinction Rachel makes contributes several important insights, the concepts of helping and service are not as cleanly separated as she seems to suggest. As another responder suggested, helpfulness may be a more important focus. By either name -- helping or service -- an act done on behalf of or for another can be expected to be 'helpful'. Perhaps we can think about both helping and service as actions performed in varying degrees of 'helpfulness'. We've all experienced someone 'helping' that wasn't helpful. Likewise, waiters and waitresses who 'serve' us may be either more or less 'helpful'. The point is that the servant or helper is 'serving' and 'helping' but the quality of the interaction is independent of the roles (and labels) of the participants.