Ahem. "Whistling past the graveyard" was me. I like credit for my cliche-deployments, I do. (grin)
My take: Whistling past said graveyard is nothing either good or bad, but where-it's-coming-from makes it so. If it's allowing you to live on that river in Egypt, it's bad, in the sense of limboizing you. If, OTOH, you're steering by that Stockdale thingy (if that's the one about 'I will eventually prevail, but current circs SUCK in the following long list of ways'), and you're using humor instead of say, rage, or total emotional collapse to cope with your fairly-fully-processed reality ... that sounds pretty healthy to me. Have at it.
The funnyman thing, again, depends. It really depends how it comes across IRL. Personally, give me a man anyday who can laugh and joke in the face of either total impending doom or everyday SNAFUs. I mean, you can't stop it, might as well enjoy the ride. Love covers a multitude of sins, but laughter is riding shotgun. I'm not down with the attitude that says you have to ACT serious to BE serious. I think it's a lot more productive to judge people by their actions or lack thereof rather than their manner when trying to determine whether they're pulling their weight/there for you or not.
ON the other hand (there's always an other hand), I've known people whose urge to be funny stems from an unhealthy (IMHO) narcissistic need to always be the center of attention with attendent audience. I'm not an audience; I'm a friend or partner. I've been around guys whose main goal in life seems to be attention at all costs, and humor is often the shortest route to that. I remember clearly being on a bus full of concert goers with another couple. Our friend pretty much ignored the three of us he was with because he could make smart remarks and attempt to crack up the strangers around him. The fact that his volume pissed a bunch of them off didn't seem to register, nor did the fact that he wasn't socially "dancing with the one who brung" him.
I don't know if any of that applies at all, because I'd have to observe you first-hand to know. Just maybe food for thought. It all depends on the motivation, I think. If something amusing comes to your mind, and you are moved to share it because why shouldn't your friends/family be amused too? -- that's cool. If there's any flavor of throwing a line in the water expecting laughter or recognition or any response at all, though ... people can sense when a response is expected of them. It feels like a form of emotional blackmail, and the quite-reasonable natural tendency is for them to get their feathers ruffled. IMHO.
"Show me a completely smooth operation and I'll show you someone who's covering mistakes. Real boats rock." -- Frank Herbert