I've been bouldering for 6 months and even I can understand what you mean a bit. I've seen it happen so many times. Id say out of every 10 new people I meet in the gym each day only 1 stays for more than a month.

Also, Ive been climbing for about 6 months and even I have noticed that it wasn't until about this last month that people in the gym have started to be a lot friendlier towards me. I definitely get this feeling sometimes that there is a sort of mind set that you need to prove that your serious about climbing before people are willing to open up to you. People just dont want to sink that much emotional energy into a person who they think only has a 10% chance of sticking around for more than a few weeks.