entitled, arrogance

What recommendations would you offer for a 7 year old boy who is often responding to situations with responses that come off as entitled and arrogant? We have taught, role played and exemplified gratitude as parents but our child often responds to special outings, family trips, treats at church or going to parties with comments like "Thanks for taking me even though I didn't like it" in a grumbling tone or "I wish I had 2 donuts and I only got 1". Do ADHD and light ODD tendencies play a part in this type of perception? We feel like it will shift in time to him being more others-focused as we continue our teaching, examples and involve him in service experiences helping others, but in the meantime we would love some help with responding to him. It's difficult to not take his comments personally, too. We are currently validating his perspective and pointing out that yes, he feels that way, and it also is rude and impolite to say things like this, especially to the host of an event. When we try to share what it would be like if he were on the receiving end of comments like this, he usually gets defensive and angry. I often get angry at the lack of gratitude and willingness to share with others and need to shift my expectations but am not sure how!