You should thank someone for inviting you to an event.
Eric is at a big sporting event with his boss that his boss gave him the ticket to.
Eric wants to enjoy the game.
Eric makes sure to thanks his boss for the ticket and offers to buy him some concessions.
Eric is so enthralled in the atmosphere and the game that he hardly pays any attention to his boss at all.
Eric's boss enjoys the time with Eric at the game and shows him more favors in the future.
Eric's boss thinks that Eric is ungrateful for the gesture and never does him any special favors again.