Do I have a responsibility to tell someone I'm not interested

[Franziska]

This is a fairly basic and easy question. Someone at work is getting friendly with me and has been asking to go for coffee, etc with me. I'm not interested in them in that way. Do I need to tell them? Perhaps they're not interested in anything more than friends (we're both single BTW)

It's a bit of a no brainer really

I would tell them...yes.

thanks, just a bit awkward if they're only interested in being friends

hmm, think i would keep making excuses, you're busy, you are going to da da.

hopefully they will get the message.

Perhaps go for a coffee and regale them with your longings for another imaginary person? If you're interested in someone else, you are de facto not interested in them.

I wouldn't want to 'make friends' either, or go for coffees I wasn't enthusiastic about. The difficulty with saying 'Are you asking me out, or just being friendly?' is that you get railroaded into furthering an acquaintance you don't especially want, while probably wondering if there was still an agenda there. I'd just keep saying 'No thanks, I prefer to read during my lunch hour' or whatever, and don't give them an 'in'. You don't have to be rude, but you don't have to be coaxed into coffees etc either.

I'd say yes if I liked their company, no otherwise. My oldest, closest friend is a man. I don't like him "in that way" but I love him as a buddy and value his friendship, if you feel you could have and want the same with this guy, why not accept? If you just don't think he's your type of friend, then keep being "busy" when you're invited out and he'll soon get the hint.

Are you interested in friendship with them? Or do you have enough friends?

I don't think you can really go for coffee 'as friends' without spelling it out first. Going for coffee is a bit datey otherwise. Just make excuses if you don't feel comfortable saying outright.

If you don't want to make an issue of it, why not suggest a friend or two join you?

That's a good tip from Debsbear, because if this person then says something about wanting it to be just the two of you then you can say, nicely, that you are not looking for a date at the moment (because sometimes saying 'I'm not interested' when an invitation has been fairly casual can lead to the other person going 'Don't flatter yourself, I was only being friendly' and unpleasantness all round). And if the other person agrees to go for coffee/lunch in a group then you can do that unless you really don't want to socialise with the person in any way.
Otherwise just keep politely refusing. If s/he gets rude or insistent, you can be a bit less gracious back and tell him/her to take the hint and stop bothering you.