Jean, for me too it was the fiber. Now that I am much better I do love Zucchini, yellow squash but I still can't find any green beans these days that aren't tough and fibrous so I am giving up on those even though I use to love them.
Along with all of those veggies I was having before I was also eating salad daily but I haven't started that back up, i'm still staying away from raw.
I use celery in cooking but I remove all of the fibrous strings before chopping.
If I have Broccoli, I definitely discard the fibrous stems and eat the florets only.