I think my problem is that I hate being aware of people going for a number 2, and so I absolutely freak out at the thought of someone being aware that I've done it. The simple fact that you can hear people going to the toilet when they are in the bathroom on the same floor as you, that it leaves a lingering smell, even spraying room freshener. It all makes me feel embarrassed and to some extent intruding.
Because of it, I regularly ignore urges to go to the loo just because I can't be in private with nobody knowing.
One time I was utterly desperate and my housemate was in, quietly working in the room next door to the bathroom, and I was paranoid that he'd hear. So I turned on the shower full, set it to spray against the wall so it was noisy, and even though I didn't hear anything, I was still convinced that he could. I left it on for a bit so I could pretend that I'd had a shower, then scampered back to my room.
This has resulted in medical issues such as fissures and minor external hemorrhoids due to retention of the faeces causing straining when I can finally bear to go. I know they're not due to anything else - I have a great conscience and thus eat loads of fibre and veg, and drink enough, and exercise.
I know that until I face this shy bowel and defeat it, these physical symptoms are not going to heal. My best bet is to keep telling myself that nobody else I know gives a damn about other people's call of nature. It is completely natural, it needs to be done, why should I be ashamed of it? Do I think any less of others because they go for a poo? No.
Just needed to get this off my chest =0)