I think the biggest key to enjoying it is not to expect them to do anything for you. Honestly, it's very random what benefits you will get (if any, sometimes) and if you go into it thinking of all the things you will get, then you're likely going to end up disappointed.
When my husband proposed to me at WDW, my mom knew ahead of time and had bought us buttons at home for us to wear to celebrate it and announce our engagement (this was before Disney made the Just Engaged buttons). My husband proposed on the first day in the parks and we wore the buttons every day after that, except for the day we spent at Blizzard Beach (can't really wear them on a bathing suit, lol). I was so excited to wear the buttons because I knew Disney did some really cool things sometimes, but I had never gotten to experience it for myself because we never went around my birthday. I was excited about being engaged and wanted the world to know! The
only time we even got acknowledged was by a nice CM at Rock 'n Roller Coaster who told us congratulations. No one else even said anything about the buttons. By the end of the trip, I was disappointed - I was expecting to really see the Disney magic and didn't find it in that part of the trip. Obviously it was still a great and wonderful trip (one of my favorites, obviously

), but my expectations not being met did leave me feeling disappointed.
In contrast, when we went for my college graduation, I wore the "I'm celebrating!" button, but didn't think anyone would notice because of my previous experience. I got asked about my button more times than I can recall. I got high fives and danced in the streets with CMs to celebrate my acheivement - and it made me feel on top of the world because it took me by surprise. And when I got free desert on the last day of our trip at Portofino, it felt like such a magical and wonderful ending. Because I didn't think they would do anything, everything they did was magnified ten times to me.
Wear the button and have a happy and magical birthday at WDW - make your own magic and be surprised by any special treatment you get.