Well them getting mad is kind of rude. They don’t need to get nasty like that

As about gifts. I either ask directly what the person needs/wants or buy something they express interest for in a conversation or if not sure I buy something small that won’t take space.

I don’t buy people books unless they requested a specific book. They might not like that book or prefer digital books. I am very particular what I read so I buy my own books, I’d not want people to buy me books.

Could you ask what they’d like next time and follow their lead? I tend to spend too much on gifts too so I’d hate to waste money if people don’t even like it