What annoys me is when I request building items and a few hours later receive energy packs. I have around 20 friends and had to request from all over a 2-3 day period just to get materials for one building!
And as to why people send 2 energy packs instead of 3 energy packs, maybe they don't know how to flip pages to see the rest of the gifts...? It can't be laziness because you can gift everyone all at once. E.g - when i receive gifts, i exit the box that asks me to send a thankyou gift, And then I go in and send the the same gift to everyone all at once. (This is after I fulfill any material requests first.)