[klapinat0r]

While I do agree with you, I think a common "gotcha" is in dealing with port forwards and firewalls.

[yuvadam]

Of course, NATs will break this type of scenario, but that can easily be solved with SSH tunneling into an accessible server.

[StavrosK]

Reverse tunnelling is more useful for this sort of scenario. Then the other person can connect to the remote server port and it'll reach you.