Gentlemen think of the people they are with and responsible for. If the girls(s) you are with are all decked out in the formal hoopskirts and such, open the door. The hoops make it hard to reach the handles, the same for in and out of chairs, her hands are busy with her stuff, and she can't grab the chair. A lot of the old rules are gone since we all wear pants now and dress fairly similarly. (heck the Possibles Bag is coming back for men, renamed the Murse?). It is taking turns in traffic when merging lanes (my lane car, their lane car, my lane car, thier lane car, my car, their lane car.......) you don't make yourself uncomfortable, but do what is necessary to excersie self restraint so you aren't running rampant over everyone else's comfort. You give up the seat on the bus to the wman with the children, or the person with the cane, because they are compromosed using their balance and you are not........ you do not shout across a room because that would step on everyone else's conversation........ You have your money for payment ready before you get to the window at the end of the line so you do not slow it down for everyone..........
Make way for the loaded person- they are clumsy with the load and you may end up in/ causing an injurious situation. You can at least get out of the way, if not share the load....... I consider the standing,sitting and other such stuff as "spy warning" stuff from the "man/women roleplays" eras. Certain subjects were not alked about between the sexes and the stand up served to interrupt/ notify to avoid taboo violation. (I still remember grandadd's reaction to the "barracks talk" in Topgun and other similar movies. He simply could not watch them with any women present- other guys okay, but "Mixed company".......)
A lot of the gentleman attitude is "common decency" not necessarily common courtesy (Yes, No, Please, Thank you stuff). You show consideration, not mouth it.