I was nervous about this because I’ve seen so many negative or average reviews on TikTok and I just, did we read the same book?!?? Because I loved this so much! 
I really enjoyed the dual timeline, I was interested in Margaret’s story and I absolutely did not see the ending coming. One of the things that really stood out to me is this idea of not leaving things unsaid, of having the difficult conversations while you have time to have them. Life is both long and short at the same time. 
Most of Emily Henry’s books are more slow burn and/or “enemies” to lovers and this could be considered a bit more “insta-lovey” but I don’t think that means the romance didn’t feel real or I felt like it suffered because of the two timelines. 
I think Alice and Hayden were just “when you know you know” vibes and I thought their romance was beautiful, tender and feet-kicking adorable. I think it makes sense that they fell hard and fast, they were on a tiny island spending a lot of time together - it’s like a whirlwind summer romance and was like a parallel to Margaret and Cosmo. 
I  loved Alice and Hayden’s ending, all the parts of it. 
Also Alice and her mum’s relationship hit really close to home for me. 
I honestly would have read 400 more pages. I loved it.