I appreciate this sounds petty but it is just something in a long line of things.
Adult son bought chips from the chip shop as he was coming home from the pub. He ate about 2/3rds and then asked if we (his parents wanted to finish them)
Said yes and I took one and then offered bag to husband, he proceeded to eat them all, I kept saying please let me have one but he refused and said I wouldn't like them.
I got cross and now he says iabu to be cross. I think it is proof of how selfish he is, he wouldn't even share something that wasn't his in the first place.