I must say I find it slightly un-easy flying over expanses of water or over urban area's more so now I have a better understanding of how an engine works and what could potentially go wrong
The important thing in flying is to always have an escape route.
Over land, it is a forced landing.
Over water, you carry a raft. Without one, you will probably die of hypothermia before they find you. For me a no-raft means no-go over any water. So, get a raft and stop worrying
There are time windows when there are no escape routes, e.g. flight over dense forests, but these are normally short (in this part of Europe). Plus quite a few departure/arrival routes...