Is it OK to return gifts to Giver?

Vampire queen, that's exactly how it was for us. I hated tinned fruit salad, my sister hated butter but when we went for tea with aunts or grandparents, we ate what we were given.
The 'accept it politely and sort it out after' rule applied too. I noticed as they grew older, that for things she really liked, one daughter would say thank you and add, "I love that" or "I always wanted one of those". For other gifts she would say thank you and add, "That's lovely" or "That's really kind of you".

Very many years ago when we were newly weds, we had the loveliest neighbours, old enough to be our grandparents. One day they invited me in for coffee and proceeded to show me some oil paintings ..... asking my opinion about each one.
I waxed lyrical about them all whilst secretly hating each and every one. "So which is your favourite"? they then ask. I chose a favourite and I'm sure you've guessed what happened next!

A couple of months later they popped it round to us on Christmas morning, beautifully gift wrapped. It never occurred to me that this was going to happen so we lived with this much disliked painting on our dining room wall for many years until they moved house!

I think always accept a gift with good grace whether you like it or not. Me? I always put gift receipts in with the gift card!

We gave DGD a present which turned out to be a duplicate. DIL was very diplomatic and said it was fine, she could play with both and make a game of it. Then I asked DGD (age 5) what she wanted me to do and she said 'take it back and change it please'.
Straight to the point and the most sensible thing to do.

I wonder how OP's Grandson feels about this, did he like the present?

Even if he didn't like it, I think it's a bad example to return the present.

My DD & I always have a present list or sometimes just one item we would like, same for her OH & DGS. Saves us all money & unwanted gifts, last Christmas I got 2 window blinds in the colours I wanted, perfect for me.

My DM now gets money or if I'm visiting (she lives 300 miles away) we go shopping, after all she's 88 so I don't mind,

I would never say I didn't like a gift or hand it back, terribly rude

I put a lot of thought into a 60th birthday gift of a book to an old Uni friend who'd invited me to her celebration. A week later it was posted back to me as she had not told me about her no gifts policy. I was surprised by how much this hurt & would never so it unless it was made clear (with a receipt) that it would be OK. I wrote her a note so she knew how I felt but she dug a deeper hole for herself with her excuses. She did say her other friends told her off for doing it.
My D-i-Ll is hard to please so at first I tried really hard to buy extra nice things. I found several if my presents in a box for the bin/recycling so I took them back. That doesn't hurt like the friend's rejection but I don't bother now & take them for a meal instead or pay for something she wants when we visit. She isn't English & her family don't make much of birthday or Xmas presents. I was cross though when she showed disdain for a birthday card sent by my sister as she couldn't understand why she'd sent it as she hardly knows her.

My MIL who passed away some years ago returned every Christmas and Birthday present we bought her saying it was "not suitable". After many years of this my DH asked her one year exactly what she wanted. She gave him instructions as to what she required, colour, style etc. even down to which store to purchase it from. Christmas present duly handed over only to be told that it was "not suitable". She never got another present from us. I hasten to add that presents from DH siblings were never returned.

I am in my 50's now and was brought up to believe that it would be incredibly rude to tell a giver that a present was unwanted! I have had this happen myself when giving a gift and I found it hurtful! As previous people have commented time effort and thought go into present choosing so a rejection of the gift feels like a comment about that! I agree that a discrete swap is fine and in the case of a child there is always a birthday party gift to find!!

Better to pre-empt the giving of a gift and ask first. No hurt feeling for anyone. If you cannot do that send money/voucher and say you thought child might be saving up for something special.

I do think it is very rude to say 'Yuk! I hate that', and believe me I have been told that a few times, especially by young parents, so I do not go there now. Why waste the time/energy/money when there is a better way?

You don't say why she wanted to give it back? Wouldn't that make a difference?

...If the son already has that particular item and doesn't need two

...If she disapproves of whatever it is

- these two examples would have two very different implications for the conversation / potential for damage that might ensue wouldn't they?

My SILs parents joined us for Christmas last year and I wanted to get them a little something. I searched high and low because I'd heard how tactless she was and bought her a collared necklace which I thought would suit her. She opened the present, took one look at it and made a disgusted face. 'Oh I don't like this', she said. I informed her tht I'd got the gift receipt and really wanted her to change it but she insisted 'no, it's alright, I'll give it to the charity shop'. I guess next year I'll buy her M & S vouchers!

Gosh that goes beyond tactless to down right rude! How ill mannered. Poor you

I bet your SIL was embarrassed nanasam by his mother's very rude behaviour.