Number 1 Dad

Earlier today as I was leaving the gas station, I held the door open for a guy coming in.  He had a t-shirt on that said Number 1 Dad on it. I continued walking through the parking lot back to my car, when i noticed another guy headed inside wearing the exact same shirt. I immediately turned around and walked back into the gas station. I was pretending like I forgot something, but I really was just waiting to see if there would be a confrontation. How can both these guys be the number 1 dad? It's not possible. There can only be one number 1. One of these guys was full of shit. I was really hoping to see a fight, but nothing happened.