People can be thoughtless around another because the other person's behavior frightens or triggers them in some way they haven't examined. Lots of people get upset when someone else is crying and just want it to "stop" so run in to see if they can get it to stop rather than thinking about what they know of the person and whether they'd like intervention or even merely asking a simple, "do you want/need help."

I didn't understand about that (and still rush in lots of times :-) until I observed my husband's versus my behavior, my "helpfulness" and my husband's stand-offishness but I know my husband is a very caring, helpful person so I wondered and finally asked him about it. He explained how he feels offering to help someone is condescending, assumes the other person needs/wants help, especially your help. He waits until someone asks for his help. I think too it has a little to do with how he was raised/his being male. I was trained by my stepmother to look around and find things that needed "doing" -- clear empty glasses, pick up trash, empty ashtrays, etc. at a party, that sort of thing so I'm always scanning my environment to see if I can "help" in any way. But I think men are not taught so much to worry about such things when they're growing up, don't offer to help their hostess in the kitchen :-) etc. But it was an interesting eye opener for me to see this other side of "help" that assuming someone else needs help because I might in the same situation is not checking reality/jumping to conclusions and can appear arrogant and condescending.