When I drink anything out of a glass or other such liquid container, that glass needs to be oriented in the proper way. I can drink from any part of the glass, but I feel mildly uncomfortable doing so. The proper orientation is as follows, in decreasing order of priority.
1. If the glass has any logos or labels or such on the side, such as a beer pint (without a handle), the label needs to be pointed away from me. If there are several labels on different sides, then the main or biggest one needs to be pointed away.
2. If the glass has a volume indicator on the side, it needs to point towards me.
3. If there is any writing etched on the bottom of the glass, it needs to be oriented outwards from me so that it can be read while drinking out of the glass. If there are several etchings, the biggest one needs to be oriented outwards.
4. If the glass has no markings on it, I can drink from any spot, but I always make sure to drink from the same spot once it has been chosen.
I don't know where I got this from, but it has been the case with me ever since I can remember. I guess it's one of those childhood things that kind of stuck. If I should get a glass in front of me that points in the wrong direction, I might make some normal conversation while seeming to dis-interestedly fiddle with the glass, but in truth I'm orienting the glass properly.
Most people who know of this pet peeve of mine consider it one of those curious little idiosyncrasies that we all have.