The list is long. Surge is a big tsundere when it comes to admit that someone is a better fighter/runner than her, but I think that's common knowledge or at least the most obvious to think about.
AU Surge never tells directly to Sonic her feelings or that he loves him. She will never do that, even after marriage. She's more someone who shows more than tell, infact she prefers to kiss him (where nobody see them) more than murmuring words through her teeth.