It is said that you should assume what you do to work for it to work.

What reasons do we have to assume that something doesn't work? Sounds counterintuitive. People will say:

I don't want to get hurt and if I assume the worst, I mentally protect myself

To this people in the pu-community reply with

It is just your ego that you are protecting, nothing serious

Rejection is part of life

Now look at this:

Rejection destabilizes our "Need to Belong." We all have a fundamental need to belong to a group. When we get rejected, this need becomes destabilized and the disconnection we feel adds to our emotional pain. Reconnecting with those who love us, or reaching out to members of groups to which we feel strong affinity and who value and accept us, has been found to soothe emotional pain after a rejection. Feeling alone and disconnected after a rejection, however, has an often overlooked impact on our behavior…

"Rejection creates surges of anger and aggression. In 2001, the Surgeon General of the U.S. issued a report stating that rejection was a greater risk for adolescent violence than drugs, poverty, or gang membership. Countless studies have demonstrated that even mild rejections lead people to take out their aggression on innocent bystanders. School shootings, violence against women, and fired workers going "postal" are other examples of the strong link between rejection and aggression. However, much of that aggression elicited by rejection is also turned inward…" (https://www.psychologytoday.com/us/blog/the-squeaky-wheel/201307/10-surprising-facts-about-rejection)

So how do you feel now, talking about rejection as if it was nothing?