The Cell Phone Book

Why is it that our cell phones have the same numbers all the time? I had never thought about it, but then, Srini just read out all the names in his call history, and it read out like the periodic table with a strict periodicity of 5. Hima, Kamal, Om, Raja, Raja, Ravi, Om, Kamal, Ravi, Ravi,... And by now, you more or less know what names to fill into the dot dot dots.
I guess most of us have similar call histories. I don't eyesdrop on other's call histories (yet), but I was just wondering, if everyone has similar call histories. Yup, once you are a part of the clique, you just hang around, and call around within your coterie. But once in a while, it just strikes me if we are becoming too exclusive. It's just the same people all the while. Am I not open anymore to people, to ideas, to ideals, to perspectives? May be I'm not.
Just a couple of days back, I had the opportunity to volunteer for the Sangam - Indian Association. Most of the people there were undergraduates with a few graduates I knew. Beleive me, I was like dumbed for the whole of the time I was volunteering there. I didn't know what I could talk about, I didn't see any common denominator linking me with them. Was I feeling too old? or too proud? or was I plain tired... of knowing all the people I do (however less it is), and just being a bubble in the pond? Insignificant, Indignant, untouched, and dying on contact with the outside world ?