He was a lump of a man, with oily skin, defeated posture and a dazed look. He ambled, sauntered, shrugged and scoffed. Most of all he just couldn't care less – what a perfect role model for a disaffected teenager

Someone asked me at a party recently which actor I rated at the moment. "Jennifer Lawrence is really something!" I chirruped. "Going out on a limb there, aren't you, pal?" came the withering reply.

I'm expecting a similar response when I tell you that Bill Murray is my role model. "Bill Murray? Really? What on earth could you find inspiring about an elusive renegade who has become the coolest movie star on the planet, and who has progressed from counterculture clown to indie mascot and now public prankster, all without any modification or compromise to his personality?" Fair point.

Except that the modern-day Murray, the one who crashes karaoke parties and Swedish golf carts alike, and who pops up uninvited at strangers' weddings to dispense relationship advice, isn't the incarnation that I idolise. Don't get me wrong: he's a hoot, and I am as prone to Bill Murray daydreams as anyone. In mine, I ask the assistant at Sainsbury's to pass me that juice carton, and when he turns around from the refrigerator it's actually Murray wearing supermarket overalls. He hands me the juice and delivers what has become his catchphrase in these situations: "No one will ever believe you."

The version of Murray that spoke to my 13-year-old self in 1984, after I'd slotted a pirated VHS cassette of his film Stripes into the top-loading video recorder, was not quite so drop-dead cool. He was more just drop-dead. But he is the one closest to my heart.

I have a mental image of myself watching Stripes, a coarse 1981 comedy about two lugs (Murray and the late Harold Ramis) who join the army. I am sprawled unwashed on the sofa in my pyjamas on a Saturday morning, sun pouring through the patio doors, leftover Frosties hardening in my breakfast bowl, noon fast approaching as my mother urges me to make the most of the day. Small wonder I felt a kinship with this lump of a man, with his oily skin, defeated posture, the eyes dazed and unfazed. The complexion must have had something to do with it. Along with James Woods, Murray is one of the great Actors Who Have Had Acne. His face is like a raggedy carpet on which a hundred stiletto heels have danced the night away. As a carbuncular teen rubbing assorted Body Shop ointments into my skin (add sugar, apply to face, rinse, repeat), the Murray mug provided a flash of pock-marked hope that coolness and acne scars might not be mutually exclusive.

As it happens, we weren't all that similar, beyond our skin and our slobbishness. Even as a young child, I was the sort of anxious person who was most worried when I had nothing to worry about; at around the time I first saw Stripes, for instance, I was given to pulling out clumps of my own hair. One glance at Murray's face in Stripes tells you that he would take many hours to understand the concept of stress – and, after you'd finished explaining it, he still wouldn't really get it. So, while I saw in him a physical parity that made him a more realistic and attainable role model than, say, Indiana Jones or the Brat Pack pretty boys, there was also the aspirational quality inherent in any act of hero worship. I wondered what it must be like to be that sort of person: to amble and saunter and plod, to shrug and scoff, to play at 33rpm rather than 45rpm all the time. To not care.

My favourite parts of Stripes are the early scenes, when his life is falling apart like a dollar bill left in the wash. He doesn't care that he's screwing up his cab-driving job: he jeopardises the safety of a snooty fare, then tosses the car keys in the river. He is half-hearted even when trying to win back his girlfriend. "You can't go," he says. "All the plants are gonna die."

In those pre-IMDb days, I tracked down some of his other films on video (Meatballs, Caddyshack) and watched them with my dad. Our tastes were often dissimilar to the point of hostility, but we could usually agree on comedy, and always on Murray's shambolic genius. At the end of that year, the rest of the UK cottoned on to Murray when Ghostbusters became a hit. I had been worried about sharing my role model with everyone else, and had wondered if he would be watered down in a blockbuster context. I needn't have worried. Murray is un-dilutable. Rather than Ghostbusters overwhelming him, his soulful comic listlessness permeates the rest of the film; few big-budget movies have felt quite so humorously enervated.

When I think of Murray, what springs to mind is a line of dialogue delivered by Elliott Gould (another ramshackle comic actor, although a much nervier one) in Robert Altman's gambling comedy California Split: "I feel like a winner but I know I look like a loser."

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