To be honest, some of these I would consider overreacting to automatically assume a gender bias because of.
“How did you learn to do all this?!”
(not to be confused with "How did you learn to do all this?!"
I've only ever heard this said in the workplace when I'd impressed someone with my knowledge of something. I've never considered it to imply "How did you [a girl] learn to do all this?!"
“Wow, you’re pretty strong!”
Because anyone as short and tiny as me showing some strength isn't surprising? Is it really sexist to acknowledge that smaller people are generally not as strong as larger people? TBH, I totally take advantage of the assumption that I am not very strong because I'm am small because I have a tendency of overdoing it and hurting myself. I would far rather have someone underestimate my physical capacity than just assume I can do something and me end up hurting myself so that I don't have to have the conversation that I'm not as strong as they think.
Others I would assume are because they are afraid of what to say to you because they legitimately don't understand what is and isn't appropriate.
“It’s not ‘P.C.’ to say this, but…”
To be fair, there are really two distinct problems that overlap: 1) inappropriate language and behavior in the work place 2) offensive language and behavior in the work place. #1 is a moving target that depends entirely on the workplace and the colleague. #2 is wrong in any workplace. I think the issues is that often times men in the workplace don't know when #1 crosses into #2 and they are afraid to say anything in fear that they will be reported for an inadvertently offensive comment. Now, some might say that if there is a question then its just not appropriate for the workplace at all, but realistically its not all black and white.
Cursing for example, I curse just as much if not more than some of my colleagues. Its not to fit in or anything like that but simply because sometimes strong language is situationally appropriate when you are fighting against Murphy's Law ever minute of the day (yeah, 3rd party custom testing is a real bitch). When your entire data set is wrong and you have to start over you're not going to just say "darn".
But when I first started at my company I wasn't going to curse my head off not knowing the temperature of the crowd (so to speak). And at first my (male) colleagues were often hesitant and halting when speaking with me and apologized profusely every time a curse word slipped. Finally in a inner department meeting a week or so in it happened again and the person who cursed looked at me and apologized again.
So I said, "Ok, I'm going to put this out there. FUCK. There, I said it. I need everyone to know that I am not going to go off on some offended rampage just because you say something I may or may not find offensive. If you say something and offend me I will tell you and we will have an honest and blunt conversation about it and unless it is something that is truly awful it will not go any further than that. I want you all to feel like you can communicate with me in the way you feel most comfortable and you can't do that if you're constantly worried about offending me."
I'm not going to say that there has been nothing that has bothered me. For example, there are a few people who will accidentally call me "honey" or some other such endearment without thinking. I just humorously deflect in a way that makes it clear I don't like that. "Honey, huh? Hey Joey, has Gregg every called you Honey?" It doesn't take much, and its just not that big of a deal.
But what bothers me is that there are women out there who have heard some of these other things:
“No, when I complain about ‘geek girls,’ I don’t mean you. You’re a real geek.”
“But—you’re way too nice to be a lesbian!”
“It’s got to be a girlfriend-proof system.”
And then didn't say a word. Maybe its not your job to fight this type of sexism, but really how is someone supposed to understand that they are saying something that is offensive to you if you don't communicate that.
Any anyone who hears this:
“You and my wife could mud-wrestle naked.”
Needs to make it very clear that that type of comment is unwanted and unwelcome. The only reason society filters out all the other awful stuff that we have in our heads is because we have been taught to be ashamed of those thoughts. You can't go back in time and have your colleagues grow up with better role models, but you can communicate when you think they are saying something unfair or wrong. If you have it in you to be offended by it you have it in you to say something.