Animations causing massive lag?

I am using a script in a seat to play animations on it in our game, and when no one in the server is sitting on a seat, the FPS doubles compared to when someone is sitting in a seat.

Here is the seat script

seat = script.Parent
function added(child)
    if (child.className=="Weld") then
        human = child.part1.Parent:FindFirstChild("Humanoid")
        if human ~= nil then
            anim = human:LoadAnimation(seat.sitanim)
            anim.Looped = true
            anim:Play()
            print("hi")
        end
     end
end

function removed(child2)
    if anim ~= nil then
        anim:Stop()
        anim:Remove()
    end
end

seat.ChildAdded:connect(added)
seat.ChildRemoved:connect(removed)

------------------------------EDIT---------------------------------

It seems like it's not the seat script, but our animation handler itself. Anyone have any ideas why an animation handler would cause so much lag when running animations in game?