What is the most useful protocol for the Internet?

I'm curious to know, what do you consider to be the most useful protocol for the Internet? With so many different protocols available, it's tough to narrow it down to just one. Do you think it's TCP/IP, which is the backbone of the Internet, allowing for the transmission of data packets between different networks? Or perhaps it's HTTP, which enables the communication between web servers and web browsers, making it possible for us to access and view webpages? Or could it be something else entirely? I'd love to hear your thoughts on this.