I was a cook in high school and later while an undergraduate. It is not a very rewarding occupation. However, I remember receiving a few tips. And they made my day. I was always conscientious about presentation and preparation, but tips were very rare. So, I began wondering, just how rare is it? As for me, if my food order is over the top in taste and presentation, I will tip. If the kitchen is close, I will stick my head in and say thank you and leave pictures of dead presidents. If the place is big and busy, I will leave something with the waitstaff with instructions to give to it the cook. But I prefer to deliver in person. How 'bout you folks? Have you ever shared the wealth with the kitchen?
Once each way.
I worked myself up from dishwasher to cook in a hometown restaurant. Just about everything was made from scratch (except the mashed potatoes, but they were still sinful). Buffet at dinner and supper (lunch was the dinner meal there), Volga-German fare always and bull fries on Wednesdays.
We served a free steak on your birthday. It wasn’t a huge cut, nor a prime cut, but it was damn decent steak. We cooked our steaks with a dash of seasoning salt and nothing else. (Aside: we didn’t use thermometers. Steak was cooked to touch, and I used the skills learned there to great effect for years afterward.) I sent out a beautifully done medium rare steak and sides.
Ledy (the waitress) came back and handed me a dollar, telling me that the patron said it was the best steak she’d ever had. That felt good.
Somewhere around fifteen years later I’m in a brewpub that I usually enjoy. Most of their food is okay, but rarely is it spectacular. Their Cajun pasta is tasty, and one can order it at different heat levels. The regular is bland, the spicy is nice, and the extra-spicy is stupidly intolerable. I placed an order for the pasta and asked for it to be halfway between spicy and extra-spicy, and the kitchen delivered perfectly. I left 30%, and called the waitress over to ensure that 10% went to the kitchen.
…and in my post-prandial collection of paraphernalia (wallet, phone, pen, etc.) I left the to-go box on the table. 
Of course.
Being in the kitchen sucks. You work harder than the servers and make less money. I hear “2.13 an hour” all the time, but they can make more in a night than I do on my entire bi-weekly paycheck. And I’ve worked front of the house. I know it’s easier. And you may not be respected like a fucking celebrity or something, but you’re treated better than the kitchen. Kitchen isn’t even human. Kitchen is completely invisible unless something is screwed up and then they get blamed, whether it’s their fault or not.
So… yes. Leave something for the kitchen. Or poke your head in and say thank you if you’re allowed. Kitchen does get paid minimum wage per hour, but that in no way means we’re paid for the work we do.
Jesus god I hate my job.
Every time I pick up a pizza to go I make sure the tip goes to the cooks. The cashier yells “for the cooks!” And they all yell “Thanks!”.
I tip my sushi chef every time I eat at the sushi bar. I’ve never requested a portion of the tip I leave go to the chef, but I have asked the wait staff to convey my compliments. More than once I’ve had a chef come to my table to talk with me about the dish and I’ve even received recipes.
Interesting concept. I’d never thought of it before. My answer is no, but because of this it likely won’t be no forever.