This is why I never use "sir" or "ma'am" or similar gender titles. Sometimes you never know, even myself being transgender sometimes I can't tell what sex a person is, not that it matter because its unimportant to me that I know. If you don't use gender pronouns or titles, no problem getting anything wrong and possibly offending anyone, well, except those that expect you to refer to them as such. But I'm not a very talkative sort so with strangers every word out of my mouth is blunt and as few as possible.
I don't get misgendered much anymore and if I have I must've not payed any attention (or simply can't remember). I do remember when first starting on my journey though, I was misgendered a lot, but only very rarely innocently by strangers, it bothered me a lot but its not their fault, they are just calling it as it seems to them, so most of the time while I didn't let it show outwardly, I did take it to heart, it hurt because I wasn't passing well enough, yet. Many times I got me into crying fits once I was alone and still thinking about it. And then of coarse their were those that did it purposely to call you out, mostly ignore those bothersome gnats.
How 'bout this, being misgendered before even coming out and living as the gender you are supposed to be. Got two examples that I can recollect and still amuse me.
There was this one time long ago while at work stocking shelves (toy store), I got mistaken for a girl. But this was at least a couple years before I even did anything towards becoming one. This big muscular dude comes up behind me and refers to me as "ma'am" and asks me about something (I long forgotten what). But when I turned around he was totally surprised to see I was a dude as well, just had really long hair. He apologies (over and over again). I shrug it off, no big deal. But he's like, "That doesn't bother you?, Heck, if someone called me ma'am I'd kick their ass." So after I helped him, I'm thinking to myself, "Does that mean I should've beat the crap out of him?" Silly, nonsense people are.
Another time was when this old lady asked for something (again at work, same job, and again can't remember what now as that was so many years ago), but it was down the arts & crafts isle. Anyway, I found what it was she was looking for, she was so happy. Get this, again not yet even showing my feminine side in any way, but had long hair, as well as some facial hair. After she helped, she replies to me, first telling me how she had asked one of the other guys in the store about where this item was but he didn't know (apparently didn't feel like helping her), several thank you's my way, and "It takes a woman". That one really amused me, she must've had really bad eyesight to not notice all the hair on my face (so I was the bearded lady). But see, that's it, it didn't bother me, not in the least.
Odd how at that time me still outwardly appearing as a guy but being misgendered as a girl didn't bother me in the least, but once I had started to live as one, even one mistaken misgendering tore me up inside, because I was a girl, not a guy, never was.