I think the main problem is that the Ergons work to keep your wrist straight and my wrists don't agree with that, especially when mtb'ing, which often sees me drop my wrist when hitting a technical section of trail. I'm used to simply resting my hand on top, rather than 'gripping' the grip, unless I'm climbing out of the saddle, where, like yourself, I like to close my hands fully.
Anyway, the Ergons seem to be the only grips that I've found uncomfortable for years, so they're soon to be replaced with some ESI silicones.
They're the GS1
I think the main problem is that the Ergons work to keep your wrist straight and my wrists don't agree with that, especially when mtb'ing, which often sees me drop my wrist when hitting a technical section of trail. I'm used to simply resting my hand on top, rather than 'gripping' the grip, unless I'm climbing out of the saddle, where, like yourself, I like to close my hands fully.
Anyway, the Ergons seem to be the only grips that I've found uncomfortable for years, so they're soon to be replaced with some ESI silicones.