In general, circuits are about galvanic closed loops. You can select any such loop you want.
Here's a GRANU schematic (generally recognized as not useful):
simulate this circuit – Schematic created using CircuitLab
A galvanic closed loop might be \$R_1\$, \$C_4\$ and \$B_1\$, for example. You can draw a circle over that to form a loop. Another loop might be just \$C_1\$ and \$R_4\$. Another loop might be \$C_2\$, \$R_5\$, \$R_4\$, and \$R_3\$, since those are also all connected and if you ignored all the other parts and wiring would form a loop. There are many loops above.
But there aren't many parallel pairs of parts. \$C_1\$ is in parallel with \$R_4\$, \$C_3\$ is in parallel with \$R_6\$, and \$C_4\$ is in parallel with \$R_7\$. That's because in all three cases there is a loop formed only by those two parts. If you cannot find a loop that involves just the two parts, then they are not in parallel with each other.
Now let's look at a different schematic:
simulate this circuit
Both resistors have the same voltage across them. But they are not in parallel with each other. Having the same voltage across a part does not mean they are in parallel. And not only do both those resistors have the same voltage across them, but they also have the exact same voltages on both ends, too. Yet they are not in parallel because you cannot draw a loop through just those two resistors. It cannot be done.
If, however, you strung a wire from the top end of one resistor to the top end of the other resistor, then they'd be in parallel.