Cancel now cancels the emote, none is an option where applicable

As discussed with @Krausus

code/datums/Emote_system/emote.dm

@@ -32,6 +32,7 @@ VampyrBytes
 
 	var/canTarget = 0		// 1 if the emote accepts a target
 	var/targetMob = 0		// 0 if target can be any atom, 1 if it has to be a mob,
+	var/mustTarget = 0		// 1 if the emote needs a target to work (won't get None as an option)
 	var/targetText = "at" // what goes inbetween user and target
 	var/takesNumber	= 0	// 1 if the emote uses a number parameter
 
@@ -124,16 +125,32 @@ VampyrBytes
 /datum/emote/proc/getTarget(var/mob/user)
 	if(user.sdisabilities & BLIND || user.blinded || user.paralysis)
 		return
+	var/list/targets = list()
+	if(!mustTarget)
+		targets += "None"
+	var/target
 	if(targetMob)
-		return getMobTarget(user)
-	return getAtomTarget(user)
-
-/datum/emote/proc/getMobTarget(var/mob/user)
-	var/mob/target = input("Select target", "Target Mob") as null|mob in view(getLoc(user))
+		target = getMobTarget(user, targets)
+	else
+		target = getAtomTarget(user, targets)
+	if(!target)
+		return INVALID
+	if(target == "None")
+		return
 	return target
 
-/datum/emote/proc/getAtomTarget(var/mob/user)
-	var/atom/target = input("Select target", "Target") as null|mob|obj|turf in oview(getLoc(user))
+/datum/emote/proc/getMobTarget(var/mob/user, var/list/targets)
+	for(var/mob/M in view(getLoc(user)))
+		targets += M
+	var/mob/target = input("Select target", "Target Mob") as null|anything in targets
+	return target
+
+
+/datum/emote/proc/getAtomTarget(var/mob/user, var/list/targets)
+	for(var/A in oview(getLoc(user)))
+		if(ismob(A) || isobj(A) || isturf(A))
+			targets += A
+	var/atom/target = input("Select target", "Target") as null|anything in targets
 	return target
 
 // returns the reason the user can't currently do the emote

code/datums/Emote_system/emotes.dm

@@ -756,6 +756,7 @@
 	selfText = "shake hands"
 	canTarget = 1
 	targetMob = 1
+	mustTarget = 1
 	targetText = "with"
 	restrained = 1
 
@@ -768,13 +769,6 @@
 	if(!. && user.r_hand)
 		return "you need your right hand free"
 
-/datum/emote/handshake/getMobTarget(var/mob/user)
-	var/mob/target = ..()
-	if(target)
-		return target
-	to_chat(user, "You need someone to shake hands with")
-	return INVALID
-
 /datum/emote/handshake/addTarget(var/mob/user, var/list/params, var/message)
 	var/mob/target = params["target"]
 	if(target.r_hand)
@@ -836,6 +830,7 @@
 	mimeSelf = "take a drag from a cigarette and blow"
 	canTarget = 1
 	targetMob = 1
+	mustTarget = 1
 	targetText = ""
 
 /datum/emote/johnny/available(var/mob/user)
@@ -844,7 +839,7 @@
 
 /datum/emote/johnny/getTarget(var/mob/user)
 	var/mob/target = ..()
-	if(target && target != user)
+	if(target != user)
 		return target
 	to_chat(user, "You need a target that isn't yourself")
 	return INVALID
@@ -1144,11 +1139,10 @@
 	if(!. && user.buckled)
 		return "you are buckled to something"
 
-/datum/emote/salute/getMobTarget(var/mob/user)
+/datum/emote/salute/getMobTarget(var/mob/user, var/list/targets)
 	var/mob/target = ..()
-	if(target == user)
-		return
-	return target
+	if(target != user)
+		return target
 
 /datum/emote/scratch
 	name = "scratch"
@@ -1342,9 +1336,11 @@
 	if(ishuman(user))
 		return 1
 
-/datum/emote/slap/getMobTarget(var/mob/user)
-	var/mob/target = input("Select target", "Target Mob") as null|mob in view(1)
-	if(!target)
+/datum/emote/slap/getMobTarget(var/mob/user, var/list/targets)
+	for(var/mob/M in view(getLoc(user), 1))
+		targets += M
+	var/mob/target = input("Select target", "Target Mob") as null|anything in targets
+	if(target == "None")
 		target = user
 	return target