Can You stop Pretending?

I'm facing social challenges now. Well, not exactly now, but it has been going on for sometime. I am realizing that as I get older, I find it harder to make friends. I am unable to find people with whom I click and who click with me. It all seems like the thing of the past: Hours of conversations, debating issues, talking openly and freely about anything under the sun, agreeing to disagree..well you get the picture. But that is not what this is about. This is about 'Pretend Friends'.
May be I just made that word up. Well, these are acquaintances who I meet more often than I would an acquaintance. Yet, we never graduated to becoming friends. They have long remained in the role and I'm having to do things with them just because. I'm sure they feel the same way about me too. Don't get me wrong. They are perfectly nice people, very helpful (when I ask for help) and sometimes fun too. But somehow, we don't have those endless conversations. I can't seem to look forward to get-togethers with them. Yet, every birthday, every festival, every idle weekend, we all seem to meet, as if we have an unbreakable pact. We drop in notes of hi/hello/how are you every now and then. But that is it. There seems to be this constant fear of revealing too much of oneself, spelling out plans for the future. May be it is just the fear of becoming friends? It is like walking on eggshells.
It goes like this: Oh, don't say this, you might offend someone in the group. I'm asking - 'So what? It is my opinion. Everyone can have an opinion right'.
Oh, we have to invite everyone, cause they invited us for their thingy. I'm asking - ' So what?, I want to spend time with people I have fun with, with people who mean something, with people I'm comfortable with. How long do I continue this act of courtesy'?
I tried thinking of several reasons why we don't click. I'm unable to put a finger on anything. We have similar tastes, interests, nothing wrong there. But we just don't gel. May be we don't do much things together other than eat, drink and be merry (rephrase, pretend to be merry). Sometimes, it gets complicated. One time, I get a feeling that we are becoming friends. But the next time we meet, I feel like I dint get the note that said ' We are back to behaving acquaintances now'. It gets really hard to gauge what to say/do.
Now, I'm getting tired of all this pretending. I want to end it. Just be plain and face the fact that we are not friends, just acquaintances. I don't have to go to every get together, I don't have to pretend and smile and show like I'm having a good time (even when I'm sometimes not!). Life is short and unpredictable. I'm sure they are also tired of all this pretending. But I'm not sure where to start/how to start. Again, the fear of offending someone rises. This is like an endless loop. Have you been in this situation?

ps: I was discussing the topic of 'Virtual Friends' with my BIL. But that is for another post..