What's 1 thing you wish you would have known before starting a food truck business?

I'm looking at starting my first food truck business with a simple menu (breakfast sandwiches, nitro cold brew coffee and bottled water/juices) targeting the AM boating crowd on their way to a popular local lake (weekends) and commercial business parking lots (weekdays).

For those who have made the jump already, what's 1 thing you wish someone would have told you before starting a food truck business?