I think you're still missing their point. Having a healthy ego isn't about never working on new stuff, or playing bad positions, it's about not being content with getting beaten even in rolling at your gym. So you playing guard when it's not what you're best at isn't wrong, it's only wrong if you say to yourself 'I'm not that good at guard so I'm not going to try and use my guard to dominate this roll, and I'm not going to be unsatisfied if my guard gets passed'. The other side of it focusing on continual improvement and not being satisfied with not getting better. That's where a lot of the focus on your A game comes from, you will eventually reach a point where playing a lot of different positions won't help you get better results and you'll have to invest your limited mat time in your main game to keep leveling up. It's not about winning gym rolls, it's about not being satisfied with poor performance because your ego tells you you should be better than that. I don't go cry in the corner when my coach passes my guard, but him passing my guard the same way over and over was a huge driver for making my guard better because I HATE getting my guard passed. If I'd said 'I need to check my ego and accept that my former Pan Am champion coach is going to pass my guard' it would have been much less of a driver for improvement. Positive ego isn't about appearances, it's not about being butt hurt that you got tapped by a blue belt, it's about recognizing that getting tapped by a blue belt means you weren't doing something right and feeling you should be better than that, driving you to improve. And a big part of improvement is just trying to win, having the will to dominate. And that is something you have to practice, and should, even though there's an element of ego to it.
IMO, "checking ego" should really mean one thing: submitting someone doesn't mean you're more of a man and being submitted doesn't make you less so. This has nothing to do with being competitive and doing your best.
Most people give their best and are competitive when playing other sports: basketball, tennis, football, pool, golf, whatever. Win or lose, its no big deal. Most people shake hands and lose no sleep over it. BJJ is a little different - there is this notion that if you tap, your life was in someone else's hands. There is a much stronger, visceral sense of being dominated and beat up. Your self worth diminishes a little. To me, checking your ego means training your mind out of this reduced self worth fallacy. It has nothing to do with being competitive or hard rolls.
You can have an ego problem and not roll hard or competitively - Those who coach during rolls, those who avoid rolling, those who say let's roll light...are all people who have ego problems but instead of rolling hard, they're more passive about tap avoidance and diminishing their self worth. Others, of course, roll super hard and never expand their games for tap avoidance and diminishing their self worth. Both are bad.
Ironically, when I tap someone, I never think or feel I'm superior, nor does my self worth increase or anything. I'm just happy I solved a difficult problem, so to speak, and overcame a really tough challenge. My respect for my training partner/competitor does not diminish one bit. And quite often, I'll submit a lower belt and think, "holy hell that was too much work - this kid's going to be a problem in a year or two!" I would guess most of you feel the same.
So let's not confuse ego with competitiveness. Nobody should be OK with losing - that's also a sign of diminished self worth. Everyone should be willing to give their all and expect everyone's all in return. Tap avoidance behavior = bad, regardless of how its expressed. Pure competitiveness, good.
