When I was younger and less experienced, I would sometimes find sex boring because the guy was either too inhibited/vanilla or he was into what I call scripted sex where things have to go a certain way for that person to get off. What I came to realize was that boring sex for me really meant disconnected sex.
Nowadays I always chat with a guy to make sure our sexual interests are compatible before agreeing to meet up. If we seem to have a connection, then I find that when we meet in person we are both mentally present. And when both of us are paying attention to what's turning each other on, good sex unfolds organically and passionately.
I always tell guys upfront that if they're welcome to check their phones as long as I get to see who they are chatting with and they can show me guys they find attractive or have played with... and vice versa. I also love asking a guy to show me what kind of porn turns him on (and i'll do the same).
The best sex for me is always that kind of connected sex that is both passionate and piggy/pervy. Never boring.