Local script inside player gui.
local player = game.Players.LocalPlayer
playerMouse = player:GetMouse()
while true do
wait()
if playerMouse.Target ~= nil then
if playerMouse.Target == "BoxOne" then
print("BoxOne is awesome")
end
end
wait()
end

3 comments
if playerMouse then dont use if playerMouse.Target ~= nil
My guess is that you forgot to actually look for the name property of the target. Try using ' if playerMouse.Target.Name == "BoxOne" then ' instead.
Use local playermouse on the top after local player