I am not sure, to Moderators, whether this thread is in the correct forum category...?
Listen, I am no expert. Maybe I should not even be replying, given my simple and uneducated approach; but I think you have this all wrong.
There is nothing wrong with wishing to be attached to someone.
You are human, so am I. We are all human, and as such we are gregarious and sociable.
We all need interaction with others, we need friends, and we enjoy the thought, as laypeople, of perhaps being able to marry and have a family.
There is nothing wrong with any of that.
When it becomes wrong, is when we make it the be-all and end-all of our objective.
we desire such things to obsession, and believe that the only way we can ever be truly happy is to accomplish those things.
'Those things', are not a problem.
Craving them to the point of obsession - is the problem.
Your hurt and upset at the reluctance of your colleague to be friendly, is a sign that you personally placed too much emphasis on desiring a result for yourself, rather than just being friendly for the sake of being friendly.
you were too 'attached' to the idea of making him your friend.
you placed the emphasis on the desire for the outcome, not the action.
Some attachments are commendable.
For example, my 'attachment' to wanting to better myself and learn more about the Dhamma, is a positive attachment.
But once I feel I have reached a position where i feel comfortable and confident, sufficiently, for myself and my own progress, I will not hold on to the attachment of wanting more knowledge.
My 'desire' will have served its purpose.
I will no longer require the raft, you see....?
Attachment can be good, but when it becomes an obsession and transforms into an 'at all costs' desire, THAT is when it becomes unhealthy.
You will not be punished FOR
your 'emotions'; you will be punished BY
Pay attention, simplify, and (Meditation instruction in a nutshell) "Mind - the Gap." ‘Absit invidia verbo’ - may ill-will be absent from the word.
And mindful of that, if I don't respond, may be why....