The analogy I will pick out of the wild blue is cooking over an outdoor wood fire vs. cooking in an indoor kitchen. Two different environments, two different overriding methodologies and two differing results. I use this analogy because smoking Q on an outdoor stick burner smoker is a hobby of mine.
There is something about headphone amp design that sucks me in. Even more than with speaker amps, the design and implementation of an exotic or bespoke headphone amp is something I find fascinating. I own five, a Little Dot (tube), a Luxman P-750u (fully balanced SS), a Violectric HPA 200 (SS), a Quicksilver (tube, of course), and a monster of an amp, an Ampsandsand Nautilus. Over the years I have owned many brands and designs of headphones and have settled mostly upon ZMF's. I have tried many brands of headphone cables including some exotic custom made cabling at uber-prices.
I mostly listen through my loudspeakers but just as sometimes I feel like getting out my Japanese hand crafted knives, All-Clad cookware, fresh vegetables, etc. to cook, say, veal sweetbreads over polenta and other times I feel like smoking a full packer brisket, it is a matter of "moods and foods". Perhaps another analogy would the best American zinfandels vs. the best Burgundies but I better stop.....
All one needs to do is spend some time at the Head-Fi site or another, forum.headphnes.com to get sucked into the downright zealotry displayed by headphone enthusiasts. Likewise, go to a CanJam or similar event and it is hard not to get hooked. By and large the headphone community tend to be younger and Asian/European. The reasons are simple; headphones don't require a room and the cost of entry into the hobby is much less.
Another gateway drug into headphone addiction is travel or commuting to work. I own a pair of custom IEM's made from foam molds of my ears. With a Ray Samuels portable headphone amp (now we get back into audio jewelry) and a good portable source (I have a Basso player) the sound is often immersive and transportive (sorry for the fancy words). And...since I often travel with my Macbook Pro, streaming Qobuz with an Audioquest Dragon Cobalt puts a big smile on my face too. The point being if you want to take your music with you, nothing beats headphones.