I tried to buy some shoes online, was told they were on back order (which is fine), then they asked for a tip. I wrote a complaint saying "you want a tip for a service you literally haven't provided on an online store with zero staff interaction". I ranted and raved about how, while the tip is optional, asking for it is like a multi-million dollar company rattling a can at me for spare change. They replied with "the tip is optional". Dogs.