I think you want a score that's a function of (a) the time spent doing the thing, (b) the time spent reminiscing about and talking about the thing, and (c) the

I think you want a score that's a function of (a) the time spent doing the thing, (b) the time spent reminiscing about and talking about the thing, and (c) the quality of the thing. A trip to Disney for somebody might conceivably be something that they remember for the rest of their lives and that has value.