Your most difficult knife to learn how to open

[Mr opinionated]

I have never had any difficulty opening knives. Be it traditional or modern flippers.
If a knife is difficult to open. That means it is crap despite the price tag. I don't buy it or get a refund lol.
Easy problem to eliminate.

 

[Phydeaux]

My grand father's slippie. It is a 3 bladed Henckles with bone scales. The back spring is very stiff and nail nicks are much narrower than newer knives.