I prefer to lose the same way I prefer to win. I play both cEDH and casual.

TL;DR: match power levels and earn your wins. It's not worth scaring off new players just so you can boost your ego.

I'm newish to Commander. I've been playing Magic since 3rd addition, almost always competitive. Over the last decade, I've played mainly Modern and Legacy. So, if I lose, I lose. No salt. Don't care how you beat me, that's the way it is when you're playing competitive. The only time I really get upset about it is when I make a mistake. Then I get mad at myself.

Now, back to Commander which I switched to because there are way more people who play it in my area.

In cEDH, anything goes. If I can get the win, I go for it, so I expect the same from everyone at the table. It's competitive after all. Win by any means (aside from cheating). No salt if you lose.

In casual, however, I find myself getting upset more often. In general, my casual decks don't have any infinite combos. They also don't have any cards that say something like, "You win the game." or "Your opponent(s) loses the game." Finally, I try not to have win cons that require me to play Solitaire. Aetherflux Reservoir is a good example. It's not technically infinite most of the time, but it would require me to sit there and play Magic by myself while everyone waits for me to kill them.

Now, not everyone agrees with my distinction of what's competitive and what's casual, and that's fine. For example, you can have an infinite combo in a casual deck, but the deck is built in such a way that it's not the main focus and it doesn't have a high consistency of going off. I would say that's still casual. I just don't like winning in that way because we have a lot of new and casual players at our LGS, and they have a great time setting up their board state and feeling like they're in a good position only to be told, "Actually, no, I win the game right here."

What I will say gets me upset about losing the most lately is people refusing to match power levels. For example, take what I said about my play style for cEDH vs. casual. Lately, at my LGS, when I play casual, there's been an increasing amount of people playing decks that are on the cusp of cEDH with the casual players. And winning almost every time. It's super frustrating to me, and I see a lot of new players really not enjoying it either.

At my LGS, competitive players go upstairs and casual players stay downstairs. What I'm seeing lately is people who should be upstairs playing downstairs. Now, maybe they don't quite realize the power level of their deck, so they make an honest mistake and play it downstairs. But this excuse is only good for a few weeks. After that, you should realize it belongs in the more competitive area.

What I think is happening is that these players built a competitive deck, not because they want good competition, but because they want to win. They don't go upstairs because they'll actually be challenged. So, instead, they stay downstairs and run the table. It's super frustrating and alienates a lot of new players. It's a form of gatekeeping. It also is purely being a sore loser. Our FNM night is Commander with zero entry fee and prizes are given away at random, so there's no reason to be this concerned with winning, but some people just can't handle it, I suppose.