For me, whenever I see mods for digital games, I usually don't like them for one reason or another(a notable exception being Kerbal Space Program, some of that stuff is legitimately awesome). But most of the time, these mods either don't add anything interesting to the game, it's usually some form of needless complexity that doesn't really improve the experience, or some form of unfair difficulty that just makes the game less good, or they just give the player some advantage they didn't previously have which is just more of a cheat than a mod.
But when I see a mod to a "Real Life" game, something like a board game or table game or something, I seem to love it. For example, this twist on pool called loop (yes, extremely clever)
It uses similar principles to the classic game, but at the same time wildly alters it with one fundamental change, an elliptical table rather than a rectangular one.
Now the game changes completely in this very strange an interesting way. Rather than just thinking simply based on the direction the player is shooting the cue ball influencing it's bounce, they now have to think in terms of that "sweet spot". It takes the core skills of pool and causes the player to build on those skills and adapt to a very interesting environmental change. It really adds this strange level of metagame to this basic formula which I find fascinating. I would love to see this become a real game, because I'd love to try it!
Another real life mod I've seen was based on a real life "patch" as it were to chess. It's called Chess Clock Jenga
Now, the last time I remember playing Jenga vanilla was possibly in 5th grade, and I didn't find it to be my particular cup of tea. This to me looks like a MASSIVE improvement. As was made evident previously, I am not a hardcore MLG Jenga player, but even I can tell that this game would be incredibly prone to a lot of down time. Time spent essentially watching other people play, and without time constraints, depending on the amount of players, and among those players, how many of them are particularly cautious or generally anxious people, one particular player could spend a LONG time not playing the game.
Generally, my rule of thumb for the quality of a turn based game is the more time spent trying to remember who's turn it is, the more boring the game is.
This rework entirely eliminates that problem. Now there is no indefinite thinking, no time to be cautious, and incentive for more strategic play. This change makes it so even if it isn't your turn, you are still thinking, and watching during your opponent's turn, planning your next move so you can execute it when your clock starts. It effectively eliminates waiting from the game, with such a relatively simple change.
Now naturally I wouldn't expect Hasbro to ship every copy of Jenga with a chess clock, as they currently have what must be the greatest ratio of cost to produce to MSRP humanly imaginable for a physical game, since they can get away with selling what is essentially a cardboard box with some completely undecorated pieces of wood that probably cost them peanuts to produce for 10 bucks. So instead, one has to "install" this mod on their own.
What I think makes these mods more interesting than their digital counterparts is that they actually add something interesting to the game. Often, I feel like some digital mods are just feats of programming over feats of game design. It's just someone who doesn't work for a game company who knows how to write a little code just making something to show off their skills. And this draws attention to a bigger point, and that is that digital games are not just computer programs. But that could be a story for another time.
Another factor that I think helps is that I find that a lot of old physical games have certain glaring flaws that make them obviously terrible games (see Monopoly and Mouse Trap), and this is probably because they came before the days of meticulous playtesting that modern games go through before they come to market. Chess took hundreds of years to evolve into what it is today, taking it's roots from many different early prototypes, and adding balancing changes along the way to make the game fair. These mods simply add something that the original designer didn't think of, or in some cases were maybe technologically impossible at the time of the game's creation.
Looking at things like this I think helps me as a designer to think about things I wouldn't otherwise consider. I feel like they are a great excercise in thinking outside the box, and perhaps sometimes thinking inside an eclipse instead.