Why some people are grumpy and crabby?

i guess we all do have grumpy days i tend to stay away from people when I am in that mode, and if I see other people are in this mode I tend to stay away from them, I try to surround myself with positives...

Some person are just naturally grumpy and crabby, and others may driven by unhappy things, such astrifling things and hard work. However, in my opinion, even if one is troubled by unhappy things, you should not present grumpy and crabby toward other people, they have no reason to tolerate you like this, and you have no reason to deliever you unhappiniess to 0thers. If one is in a bad mood, my suggestion is do someting to let it out till you feel better, for example ,yelling in an open field, break something(a bowl),or just go shopping.And then come back with a smiling face to people. But if you do meet a grumpy and crabby person, just do not to take notice of him/her, he/she doesn't derserve it .

I don't know why people are like that. Theres a lady who runs the local tag office.I swear I hate going in there because she is so rude and hateful. She stays that way. I always go in with a smile and greet her very nicely and I never receive a smile or anything. She's rather snotty and I'm glad I only have to go in there twice a year. April, (oh no thats just next month!!)and again in May to get our cars tagged.

I have days that I am extremely grumpy and I know that it is not pleasant to be around me when I am like that but I sometimes can't help it. I work a lot of hours between work,home schooling kids, housework, running errands, etc. so I feel that if I am grumpy the ones around me should understand why. I am usually up all day and night days a week so I am always tired and I think that leads to being grumpy.