If I don't like the person concerned, I hate them to touch me. There was some bigwig female came over here from another department, all feisty and full of herself....she was being patronising and then she briefly touched me. I just thought "who the hell do you think you are?" If it hadn't been such a shock I'd have probably blown her off, but I tend to just freeze up at such times......I tend not to trust my anger enough to give it an immediate venting, and prefer to go away and think about it before deciding what to say about it.
On the other hand, just touching me suddenly isn't going to upset me if I like you, and I like most of the people I hang around with. There was one lady who very bashfully and clumsily cuddled me for the first time. It made me feel tense and awkward....my response seemed to put her off trying to do it again for quite a long time. But I wasn't in any way offended by her approach, and we did eventually cuddle again. Once more it felt extremely awkward and her body seemed so delicate tnat I feared I might squash her (I'm more into a good, firm grapple than a light embrace), but the following time we were much more relaxed about it, and now we cuddle every time we meet and it feels perfectly natural.
I think the best thing is to abide by a rule here - never grab anybody without some kind of warning. Otherwise the other person can easily feel trapped and molested, because they can't withdraw with any grace. Instead, spread your arms slightly and move slowly towards them......and back off if there's any sign of reluctance or anxiety.