Hey there atxflyfish. I can see your concern. Im sure that there are others that can offer further advice than I can. That being said Ill give my two cents.
Often times when you get into a situation where mending is involved is when you have a cast upstream and across a quick section of water to a slower section. Youll have to strip your line to keep the slack out of it, but youll have to mend your line to keep the fast water from pulling your fly through the slow water, which will look a little odd to your prey.
Mending your line, when done properly, will actually help you in setting the hook because you will be keeping your line straighter and in more control.
I hope this helps and I hope I explained everything clearly enough and didn't confuse you.