I think these two may be my favorite so far (need to reread book 3 next to find out because I know I love them too). But there's just something about this brother's best friend to benefits to best friends to lovers story... Garrett and Jennie are so perfect together and share the kind of love I'd be thrilled to find some day. I relate to parts of Jennie and admire her personal journey. Also, the spice is spicing and we love that here. 
Reread 2025: what she said (above) but with confirmation that these two are, indeed, my favorite. The way they become best friends and that's the base of their relationship is beautiful. And as usual, the found family aspect of this book is incredible; the hockey boys are hilarious and goofy, the girls are fierce, and Hank is the best.