Fucking Nodders!

Ok, so I’d like peoples view on the following scenario…

You’re riding along and sense a fellow rider on your wheel. They move out to overtake you however they not travelling fast enough to make it quick and decisive. You slow down once they're alongside as they start pulling in across you. Once in front they slow forcing you to reduce the pace you were at before they overtook. You are then forced to either stay at that pace or re-overtake...

Should you get annoyed or should you just get on with it?

Sit on their wheel for 30 seconds, take a breather before leaving them in your wake.
Or speed up so they have to drop back. Depends on how fast you are going when they attempt to overtake you