The end is nigh. On Friday, millions of us will abandon all semblance of dignity, good manners and common sense, as the country becomes a hellscape of canoodlers, nitpickers and philanderers. That’s right: Valentine’s Day is upon us.

Restaurant staff see the worst of this annual depravity. From their vantage point, 14 February is less a celebration of romance, more the night each year when one questions whether humans deserve love at all. We’re not all complete savages – it is just that heightened expectations make us act strangely.

“You can tell people are trying harder than usual,” says Katie Toogood, co-owner of the Prawn on the Lawn seafood joints in London and Cornwall. Obviously, it’s nice to make an effort, but too often this tips into tedious perfectionism. Giotto Giannandrea, a waiter at Lina Stores in London, notes that lovestruck diners become fixated on securing a special table, automatically rejecting the perfectly fine spot they are first offered in favour of an imagined superior setting. “It’s not the table that makes a date,” he says wisely, adding that people should quit fretting. “I’m not going to sit you in the toilet.”

Pressure is no doubt also to blame for an ailment that affects men around this time of year: loudly complaining that the wine is corked (even when it’s not) in order to impress a date. And, yes, while #notallmen are culpable, it is “100% always guys” who do this, according to a waitress-turned-PR who asked to remain anonymous. She recalls a punter who vociferously insisted that his wine was corked, despite it coming from a screw-capped bottle. “Usually we’d have glossed over something like that, but he was quite rude, so my colleague called him out on it,” she says.

Josh Stephenson-Roberts of Osteria Tufo in north London confirms that behaviour of this kind is a Valentine’s Day staple. “On a new date you will get the guy rejecting the wine.” He finds it funny – but if you are going to try it, first check the bottle was sealed with a cork.

Understandably, many of us want the evening to look memorable – hence our weakness for over-the-top table decorations. Phoebe Somerfield worked in a restaurant in Devon where every year a regular would deck out her and her husband’s table with “ginormous gold, glittery balloons” and scatter the area with confetti. “The tables were really close together, so we had to fight around the balloons,” Somerfield says, groaning.

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Rachael Gibbon, the general manager of London’s Honey & Co restaurant group, had to deal with a man who festooned the table with rose petals – one for every month he and his girlfriend had been together, he explained. Gibbon was worried about his partner’s reaction, but the abundance of petals proved reassuring. “It was quite a lot, so I thought: she’ll know what he’s like by now,” she says.

Should you avoid decorations altogether? No – the consensus is that they are OK as long as you ask first. But think twice before involving confetti. “People don’t realise how annoying it is to sweep up,” says Somerfield.

While some of us make too much effort on Valentine’s Day, others haven’t even mastered the first rule of dating: don’t perv on someone who is not your partner. Stephenson-Roberts observes that “wandering eyes” are a common feature of the evening. Digital flirting isn’t unheard of, either. Peppe Corallo, bar manager at London’s Kitchen at Holmes, remembers one woman who suddenly started screaming at her boyfriend during dinner. Why? He had been checking Tinder at the table. She hurled her champagne in his face before storming out. Unsurprisingly, her sodden lover soon paid up and left too. “I felt bad for him in some ways, but at the same time, don’t put your phone on the table where your girlfriend can see,” Corallo advises.

Avoid standing someone up, too – although if you are the one who gets ditched, all may not be lost. Stephen Tozer of Maison Bab in Soho, London, had a diner whose date didn’t turn up last Valentine’s Day. He eventually confided his plight to the waiters – and they moved him to a more sociable spot at the bar and fed him margaritas on the house. “He was sat next to this girl, got chatting to her and ended up leaving with her,” Tozer says. Don’t suffer in silence if you’re in a similar boat, he says – chances are company is on hand if you want it. “Anyone in the hospitality industry wants to show someone a good time.”

Predictably, Valentine’s Day encourages public displays of affection. The anonymous waitress-turned-PR has unpleasant memories of a couple who, after sequestering themselves in a cosy downstairs nook of the restaurant, immediately started fondling each another. Unfortunately, diners in the mezzanine area had a direct view. Most found it amusing, but she reckons it is still wise to keep embraces “within the boundaries of what you would do on a normal day”.

It is standard to choose a restaurant based on the food, but bear in mind your history with the place. Last year, Gibbon had to move a flustered woman and her paramour to a less conspicuous table; the diner had spotted an old flame across the room. “She said they’d had their first date here so they obviously both liked it,” Gibbon explains, which says good things about the restaurant, but less good things about the duo’s restaurant-selection skills. It is frankly masochistic to revisit your ex’s favourite spot.

Ultimately, there’s no antidote to the mind-altering poison that is Valentine’s Day. If you must go out, act as you would on a less hyped occasion. You could also try mastering simple restaurant etiquette. Don’t spend ages pondering your meal choice or quibbling over the bill (dithering is “really irritating” on busy nights, says Somerfield). Nor should you let romantic cliches trick you into aping tired gender stereotypes – or, as sommelier Josh Castle puts it: “Don’t use the phrase: ‘And she’ll have …’ – let your partner order for themselves.” It is Valentine’s Day, not 1950.

If all else fails, take comfort in the fact that while your temporary lunacy may annoy some, it makes the evening a cherished spectator sport for others. Somerfield is already looking forward to this year’s entertainment. “People do special things,” she says, her emphasis suggesting that “weird” might be more accurate. “It’s quite an interesting evening.”