Think of mental resilience as being a raft.
Everything happening around you is the ocean.
At first your raft is a few planks of wood, strung together. Your raft is very unstable so even small waves tip you over. You are clinging on to your raft in fear of drowning.
As you build mental resilience, your raft gets stronger and more stable.
You have put some work in. Perhaps your few planks are now a rowing boat. You can ride over small waves, but big ones still tip you over. Your rowing boat is stable, but if you walk too close to the edge it tips over. If the wood isn’t treated well, it can rot and fall away.
Eventually you are sailing around in a yacht or an ocean liner. It is still possible for events outside your control to sink you, but you don’t worry about them anymore. They’re just things that happen outside your control.
Finally, you can enjoy the ocean.