If you take a look back at your life, or even your life right now.... if you examine all the things that ever happened that you were UPSET about, you will find that every single one of them was because some form of SEPARATION was happening.
Grief and loss from the death of someone you know, arose because of a sense of separation or ending.
Being in a panic over losing a job, entering into fear, was a condition of separation from safety and abundance.
Fighting with a coworker over some stupid power struggle, was all to do with you seeing each other as having separate interests.
All sense of unworthiness that came from rejection or abandonment, was all to do with you seeming to be separate from value or separate from that which values (God).
In every case, EVERY case, every single 'form' of upset, although they all look very different and you have many many different words to describe the 'specifics' of a situation, ALL of them were forms of separation in one way or another.
That is because the ONLY problem is separation. And it is only ONE problem. And it has one solution: healing/unity/atonement.
So really, each time we get upset, we need to realize, this isn't really an isolated upset. This isn't a unique upset that is unlike all the others. In fact, it's just another form of the same problem. It's just one more disguised, distorted variation of the same single problem, the same single temptation, the same single puzzle, which is being presented to you by the ego. It only has this one tool to use against you, so it dresses it up in different 'forms and specifics' to try to get you to believe that this isn't the same problem that you encountered last time. It's very deceptive that way. Appearances are very deceptive.
Look deeper. This upset about money is the same as the upset about your parents, the same as the upset about someone dying, the same as the upset about lacking friends, the same as the upset about becoming sick, the same as the upset about something you saw on the news etc. We are so deceived by the ILLUSION of appearances... based on forms ("nothing so blinding as sight of form" - ACIM), that we do not see the similarities. We do not see the generalization of the lesson. We do not realize.. ..."its all the same trick". It's the same single trick, just one problem showing up in different disguises.
If you can latch onto that, which the ego DOES NOT want you to realize, which is the whole point of why it uses ILLUSIONS to create the ILLUSION that there are many many many completely separate problems, then you are homing in on the underlying single 'issue' that needs to be RECOGNIZED as the same single issue. The single CORE of the ego. The one problem of separation from God, from which AAAAAAALL other suffering stems. ALL of it. And thus you need but one solution. IF you can recognize all problems as one problem, then you will become willing to surrender them all in favor of the ONE SOLUTION, which is Holy Spirit.
The truth is quite abstract. Don't be fooled by a world of illusions!