Many mountaineers are obsessed with completing lists -- for instance, summitting every peak above a certain elevation in a particular region. Peakbaggers aspire to climb all 12 peaks above 14,000 feet in California, all 53 peaks above 14,000 feet in Colorado, and many have died trying to summit all 14 peaks above 8,000 meters in the Himalayas. But to me, these lists are extremely arbitrary. What, for instance, is so important about 14,000 feet? Why not 13,900 feet? Or 14,100 feet? Being cleanly divisible by 1,000 does not seem especially significant.
The length of one foot is itself an arbitrary convention. For whatever reason, people agreed that one foot is 12 inches, but there would have been nothing unnatural with setting it at 13 inches. In which case, no peaks in California would reach 14,000 feet. To make matters worse, in order for a peak to "count" as a 14er, it has to rise a certain distance above the saddle connecting it to a higher 14er. In California, if this distance (the peak's prominence) is set at 200 feet, then Thunderbolt Peak "counts", but not if it is set at 300 feet.
Climbing a mountain, or a lot of mountains, can be valuable in its own right. For some reason having to do with human nature, climbing mountains that fulfill certain numerical thresholds seems to add a layer of value to the experience. Why that is the case is a topic for further reflection.