Thanking a user is too hard, and requires a confirmation step. This is unlike any site where similar functionality exists.
Recommendation : hold thank action in a queue for 30 seconds (60?) in which the thanker can click "thanked" to unthank with no notification sent to the target of the thanks. After the queue expires, the user can unthank but no action will occur other than "Thanked" changing back to "Thank"
Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=47658
https://bugzilla.wikimedia.org/show_bug.cgi?id=59807
https://bugzilla.wikimedia.org/show_bug.cgi?id=71360