An idiom used when an observer notices their friend engaged in an extremely self-centered digression. Serves as a reality check. Inspired through the interactions of siblings: Charlene and Sherwin.
Sherwin: And then, at the tender age of 12, I got my black belt in teakwondo, and then I won a bunch of awards in school and soon you'll be calling me Dr. Sherwin.
Charlene: Well "it's all about meee meee meee" isn't it?
A popular alternative for saying everything is okay. Equivalent to "no worries".
"Rainbow" is often used as a substitute for people with iOS5 who do not have access to the rainbow emoji.
Gravy is a sauce made from the juices of meat or vegetables and enhances the flavour of a meal. In poorer times, to have gravy on your meal is a sign that you have sufficient meat and vegetables to make such a nice meal. Hence the phrase "on the gravy train" meaning that ones life was well supplied with good things, usually money.
"It's all gravy" therefore means that there is an abundance of good things in the given circumstance.
It should not be taken to mean that there is no problem or that a situation is liked, specifically. Those things may follow but are not necessarily connected.
A: We just secured a lucrative contract with the supplier with an open ended term.
B: It's all gravy from here on, boys.