Why are people only interested in making a 'half-hearted' effort

I know this probably sounds as if I've analysed this quite a bit, however I have noticed when it comes to things that are potentially important to me like 'career' or 'socialising' then people don't take me as seriously as others and they only put in half the effort to make sure things go as smoothly and troublesome free as possible.

For example, a friend of mine with lupus, takes my sister's career very seriously and gives her time and space to get used to her new job and also observes when she's having a busy period working that she may be busy and can't communicate back as easily or frequently. However, when it's my turn to start a new career unless I'm in constant contact with all my friends, like I am when I'm not working then they think that I'm having a hard time at work. Also when I am having a lot of work on at work or it's a busy period they expect me to also be in very frequent contant with them!!! Do they think I've got more than 2 pairs of hands/ do they think I'm extra brainy and can cope with pressure from them as well as pressure from work. The harsh reality is NO I can't cope even with work's pressure and because my friend turns up almost in rags to every work place I start work in, it gives a really really bad impression to my employer as I make sure I'm always fairly well turned out.

It's small things like this that really get me down sometimes. Why can't people give me a fair chance like everyone else?
Why can't people trust that if they havent' heard from me for a few weeks that everything might actually be ok with me and there's no need to panic!

Another thing that gets me down sometimes, is I know lots of people in the street to say hi and maybe talk to for about 15 mins to 30 mins however noone ever wants to go around each others houses or meet up for a meal or a coffee! I only have 2 friedsn who frequently want to meet up for a coffee or for a meal or spend a few hours with each other.

Oh well... anyone else experiencing this?