Both are not socially accepted, and the later one smells nastier that the first one. But there are people who are so relax and just letting their gas out in public to the point that you feel shame for them.
One slow day in my work place when we are busy cleaning-up, tidying the displays and putting back clothes. I heard this loud familiar sound, I know it's fart and I know who did it. When I look at her, she is in her pace as if nothing had happen and she did it one more time and it's loud. It made me think for a moment if which is disgusting and un-accepted, burping or farting, I believe both of them.