Unless something is deliberately obviously mean (like buying a vegan a stake) I think 'worst' is subjective and you should be careful not to be ungrateful as its never becoming.
For example:
Last year we tried the whole de-cluttering thing and I had a massive toiletries clean out, god rid of about 40 bottle of barely used stuff (and gave away like 5 new unopened box sets of toiletries) since I only ever use the same couple of items.
Then for Xmas right after my IL bought me a pretty Xmas themed toiletry hamper of a brand I never use.
Its funny more than 'offensive' as they meant no harm. Yes I was mildly irritated at having to house like 10 new toiletry things I have no use for but it doesn't mean it was a 'bad' gift in general and I wouldn't tell them, it was just a not a great gift for me at that time. Ironically if not for having specifically put the effort into de-cluttering I wouldn't have even thought twice about it and it would have just got crammed with the others.