All I did was forget to water it on just one day last week. That was enough. It dried up and died.
I bought another one this morning. Praying for rain every day for the next week so it can get itself established. I'm not always the best at remembering to water stuff.
At the opposite end of the water-loving scale, I bought some lavender this morning as well. It doesn't like much water at all, so I need to work out a way to keep it as dry as possible. No problems. I think this plant might like my forgetful watering habits.