My granddad and my dad carried a big Case pocket knife.  They both had a good use for one.  My granddad was a fisherman and used his every time he was fishing, which was 3 to 4 times a week.  Rain or shine.  Hot or cold.  My dad was an electrician and used his at work.
I wasn’t like either of them.  I spent my days behind a desk in an office.  Still, I had use for a small pocket knife, some time called a “pen knife.”  I used it for cleaning my fingernails, opening packages, mail, and so on.  
My knives:
From bottom to top:
The first knife was an old Case “pen knife” which I used for 15 years.
The second knife is a Browning which I used for about 10 years.
The third is a small Swiss pocket knife, which has a knife blade, a combination screwdriver head and fingernail file, scissors, tweezers, and a toothpick.  I’ve been using it ever since, and I don’t go a day without using it for something.  It's very handy to have in one's pocket.
The top knife is a classic French Laguiole.  It’ my BBQ eating knife.  Why?  For two reasons; First, I just like to looks of it.  And second, my favorite BBQ joint serves the meat on butcher paper with a flimsy plastic knife, and I enjoy finding a good use for the Laguiole because it actually works to cut sausage and beef brisket.  Then comes the tricky part: using the knife as a fork.
The End.