I’m not sure this has been mentioned.
Because we believe that the Eucharist is holy, we show it reverence before we enter a pew and take our seats, prior to any praying and adoration.
This is usually done by bowing slightly at the waist in the direction of the exposed Eucharist or the Tabernacle before entering the pew and sitting down. A second better method (for those capable of it) is to genuflect on one knee, down to the floor, again in the direction of the exposed Eucharist or the Tabernacle. Some will go farther and go down on both knees, and bow to the floor, with hands clasped in a prayerful position.
Then repeat on your way out.
If you enter a Catholic Church for any reason, and the Holy Eucharist is not exposed, and you can’t spot the tabernacle, then bowing in the direction of the altar is appropriate.
Obviously non-Catholics should do what is comfortable, but don’t be surprised when you see Catholics do the above.