I didn't retire - couldn't fly, so no career possibility - did my 3 years (Vietnam ended, a RIF let me out a year early.) But those 3 years were a tremendous first job, and what I learned helped me throughout my life. I'm not sure I've ever completely left it behind.
Group trips require a great deal of compromise, more than a trip with one or two others. (For me, the big compromise is having a campfire. I don't light them myself, partly because they're too much like work and partly because I don't like the smoky smell that gets in everything.) However, if you're lucky, you'll meet one or two people you'll hit it off with - and then I get to take the trips I really enjoy. That's how it worked with me.