I work at Microsoft and we have pretty strict guidelines on interview protocol from our side - we are encouraged to stick to objective stuff, and not focus on soft skills - to put candidates at ease but also challenge them for clear answers and approach. I'm what's called an "as-ap" interviewer which means that I can come in at the end of the day, interview the candidate (who will have been in several other interviews) and answer their questions as well as to get a sense for team fit and persona, without forcing those criteria -but of course it IS important the person be a functional colleague for a team.
I'm very serious about the process and while I think it's the absolute bottom criteria in an interview, the way you dress CAN make an impact on the people you meet and interact with throughout the process and extremes can tell us a lot. You won't get dinged for tattoos or piercings or any of that stuff, but depending on the job we expect a reasonable level of personal appearance for the interview as a sort of formality to show effort if nothing else. We encourage people NOT to wear suits or to go to any expense - but to wear something comfortable and the sort of "best version of what you'd probably wear to work" - which in our case means looking something like the other engineers, artists, designers and so on in the office.
If somebody showed up wearing like, denim cutoffs and tevas with socks and a t-shirt with a swear word on it - I would personally take note of it, but it wouldn't affect your interview unless all the other candidates were exactly as good and no other criteria differentiated them (impossible).
I have a subjective vision of what constitutes the right apparel for interviewing in the tech field, but I don't want to present it as a fait accomplish since it is subjective, but if you dressed like this for an interview with me, you'd get brownie points at the very least and frankly it would tell me you'd at least considered it and taken the interview and our time seriously:
Spoilered so it doesn't claim any authority for the thread.