Sure, I like to fly first class.  I'll pay $125 or $250 no problem one way to upgrade as I just did on a trip to Phoenix or $2200 RT on a Miami - Buenos Aires trip on Aerolineas Argentinas last year.

But I don't get those making crazy efforts to maintain their elite status on the airline of their choice.  From the New Yorker: 

The costliest manifestations of GS-MAD are unnecessary year-end trips, called mileage runs in the frequent-flier community, which are cousins to the flights Walter Kirns protagonist in Up in the Air takes to meet his goal of a million lifetime miles. I asked around to find the highest amount anyone had heard of being spent on mileage runs: the winner was fifteen thousand dollars, by a friend of a friend, in a month. Another friend told me about his own bottoming out, in the pre-Global Services era, when, in an attempt to achieve the highest status level at Continental before it merged with United, he took advantage of a temporary quirk. At the time, Continental, engaged in a route war with Southwest, was flying connecting flights between Houstons two airports. Just shy of the requisite number of flight segments, my friend flew three round trips in one day without ever leaving town. The planes were filled with others doing the same, like some mile-oholic version of The Iceman Cometh.