Do people often mistake friendliness with being flirtatious?

Today I was serving this guy at my job and I was waiting for his transaction to go through and he goes “You’re just sitting there smiling.” And I wasn’t smiling but more so waiting with a friendly/patient look to make it less awkward and I tell him “No I’m just waiting on you.” And he just says “Don’t play with me girl because you can get it.” Lmaoo and he just walks off and I was confused because I wasn’t even trying to flirt with him but that’s the vibe he got from me.
Do people often mistake friendliness with being flirtatious?
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