Bind "Yes" to your emote wheel. You're welcome.
Wait, you mean people just walked away from an emote quest because they didn't try every single emote first? I mean, I didn't knew what to emote either but simply going through all of them popped the chest eventually. Only way I can understand is if it's one of the emotes that isn't assigned to your emote-wheel by default and didn't knew you had a couple more.
There's another one at the Zakarum Chapel where you have to emote in front of the statue. It took me like 15 tries till I found out that it wants to use "beckon". Saw two other people stuck there too and when I emoted beckon (your char says "Follow me") they emoted yes and tried to follow me lol. Told them it's for the statue so we all got our chest in the end but it was funny.