When I was a little girl my grandmother used to say “listen with your ears not with your mouth.” I’ve been at sessions where I wish I could say something similar to some of the musicians around me like “listen with your ears not with your instrument.”
If you listen to as much Irish music as I do, you’ll know each different musician or band has a different style of playing the tunes. Maybe one puts a swing in their reels or elongates the first beat of a jig. It’s no different at a session. Whoever is leading the tune may have a slightly different view of the tune than you do. So if you swing your reels and the person leading the tune doesn’t, something’s got to give, otherwise its a train wreck.
Often times we spend so much time practicing tunes by ourselves that we get to the session and all we want to do is play it the way we learned it. So we put ourselves out there and play our hearts out. The truth is though a big part of participating in a session is listening to the music around you.
Pay attention to whether it is a jig, reel, hornpipe or polka and listen to the beat. Not everything is in 4/4. And even though a reel and a hornpipe are, there are differences between the two. So take a step back and listen to what is being played. It’s okay to step off a little and not play for a few minutes. Remember, there is beauty in the white space.
Session Obsession 
Well done, Katrina. That’s a good observation.