There are obviously ways you could have reduced your spending here, but I'm not so sure it's worth it. If you generally have your finances in order, $100 for an occasional (1-2x a year, not 1-2x a week) night out with friends isn't a big deal. Pick your battles. I almost never go out to eat/drink, but a friend from overseas was in town a couple weeks ago and I had no problem spending ~$150 on a day out and about with him and some friends.
The problem is when the "occasional" birthday or friend event ends up happening every couple weeks. I struggled with that when I first started on MMM. Each friend might only want to go do something like that every 2 months, but if you have 6 separate friends who think that, it ends up being every week or two. I did have a few friends bitching at me "Come on, it's just this one time, you never want to do stuff!" I finally told a few of them my position of "Yeah it's only 2-3x a year for you, but there's 4 other people saying the same thing, so it ends up being all the time" and basically got an "Oh cry me a river" type response.
I started inviting them over for dinner where me and my girlfriend would cook, and call them "family dinners." The idea works well, and we do that about once a month now. Learn to cook, and have them bring the beer.