When you get surprised in the opening

If I constantly get into problems when I get surprised by an opening variation, what would be the generally recommended course of action? Maybe it's not as bad a position as I tend to think, but some positions typically throw me for a spin, and if I thought I'd prevent it but then it appears anyway somehow, then what?

The problem might not be in the opening itself, but I seem to be bad at basic opening logic, or I see ghosts... or maybe I'd have won if I was generally better at tactics and stuff? I know some advice would depend on other factors in the game generally, but I'm interested in what you could give me as the default advice when in a dilemma. Something like "just capture the Bishop" or "monitor this and this pawn, and if Knight here, then your Knight ALWAYS here" or "ditch the opening"? I don't know, I just know it sucks to have to deal with unexpected stuff so early on... and I already study openings more than everything else, probably.

Thanks for the insight!

For some reason, most of the books I had checked recommended the dropping of the Bishop back to Bg3, so I took that almost as a rule of thumb. I've seen some Slav structures in which Black allows the Bf5 to be captured by a Knight in order to recapture with a pawn and set up pretty much the same structure you showed in the second example, only from the other side of the board.

Still, another possibility comes to mind:

I was too tired to realise it last night, probably; but now it seems to be an easy conclusion.

Okay, new example from today:

This really grinds my gears. How do I stop getting confused an tilted in the opening?

As a Lion player, I am aware of that strategic concept, yeah... but damn, always with the queenside suggestions. I just don't think Black should just be able to get such a kingside aggression-oriented position for free, because I sure as hell never do as Black.

One of my main reasons for playing 1. d4 is the control over the e5-square. If White has it, his attacking chances are generally very good if Black castles kingside; if Black has it, he holds. The reverse goes for the e4-square, but it's less important since White has the slight advantage in initiative by default. 1. Nf3 also tries to control e5, but it also leaves e4 weaker, and I wanna be able to play a quick f3 early on and not allow Black lines in which he lodges his Knight on e4 and then plays f5. I'd much rather avoid that possibility altogether.

Now, imagine playing your opening with such a clear strategic goal, then getting that positional perk straight-up denied by the means of some wonky transposition? Of course you'd feel bad!

So there, I found an improvement, but only after losing beforehand. I'd like to attain the insight that would let me play such positions well from the get-go, but hey, I guess I have to get duped in order to undupe myself.