For me I just cant help myself .... I would look at the whatever I purchased with BTC and 5 years later think well that was the most expensive X ever.
Once you've reached a certain plateau does that really matter any more? I assume for most people here it would be a house or two, enough to pay living costs forever and the purchase of a small Asian woman run her little fingers all over your willy.
Beyond that it becomes somewhat academic. I had a £200 Amazon gift card the other day and in the end gave it to someone else because there was genuinely nothing I wanted on the entire site so lord knows what I'd do with trillions, probably troll the Bitcoin markets by gulping up all the sell walls.