Literally everything that comes with having IBS/colitis: Yes, I (desperately) need to go to the toilet. No, it can't wait. Yes, I just went an hour/half an hour/five minutes ago. No, I can't just hold it in. Yes, it takes me longer than 30 seconds. No, I did not drown in the toilet.
Edit: Oh and of course the answer to "Where were you so long? / What did you do so long?". I took a shit, Susan. What do you think I do for 15 minutes on the toilet? Pray? Sleep?
After seven years, I don't even care anymore about social norms. If I was on the toilet and you know and still decide to ask, I will answer you honestly and without mincing my words.