Coffee shops may feel cozy and casual, but one etiquette expert says too many customers forget they are still shared public spaces."Coffee shops may feel like our living rooms, but they're really shared living rooms — and shared spaces work best when everyone remembers their manners," California-based etiquette expert Lisa Mirza Grotts told Fox News Digital.In a recent blog post, Grotts said even well-meaning customers often break unwritten rules without realizing it. "Public spaces require extra awareness," she said.RESTAURANT TIPPING CONFUSION SOLVED: EXPERTS REVEAL WHEN YOU SHOULD GIVE MOREHere are five common habits she says customers should stop.Customers should decide on their drink — including size and any sweetness adjustments — before stepping up to the counter, Grotts said. "Awareness saves everyone from unnecessary tension."She advises following what she calls the "three P's": "be prepared, present, and polite." "Know what you want before you reach the counter, put your phone away — unless you're using it to pay — make eye contact, and say 'please' and 'thank you,'" she added. HOT DEBATE ABOUT 'NIGHTMARE' PLANE PASSENGER ERUPTS AFTER MAN BREWS ESPRESSO AT 35,000 FEET"Coffee shops operate on flow," Grotts said in her post. "When one customer hesitates at the counter, it disrupts the rhythm for everyone behind them. A moment of awareness keeps the line — and the mood — moving."Good manners are really about awareness, Grotts said. "Recognizing that baristas are working hard, and that other customers are waiting their turn. You’re one in a line of many."CLICK HERE TO SIGN UP FOR OUR LIFESTYLE NEWSLETTERGrotts said these small courtesies help keep the line moving and make the experience better for everyone.The coffee shop is not your living room or personal office, Grotts said."Shared spaces come with shared responsibility," she said. "Clean up after yourself, keep conversations at a reasonable volume, and treat staff respectfully. These small behaviors show that you recognize you’re part of a community; not the only person in the room."CLICK HERE FOR MORE LIFESTYLE STORIESCoffee culture has made highly customized drinks the norm, but Grotts said timing should guide how elaborate a request becomes and that courtesy matters most when others are waiting.TEST YOURSELF WITH OUR LATEST LIFESTYLE QUIZ"Etiquette is really about reading the room and recognizing that your choices affect other people’s time," she added. "If the line is long, keeping your order simple is thoughtful, especially if you’re ordering something you get regularly.""It’s rude when a café becomes a rent-free workspace," Grotts said. "The unspoken agreement is simple: you purchase, they welcome you. You linger, you replenish. Repeat as needed."A good rule of thumb is to order something when you first sit down and to make another purchase about every hour you stay there, she said. During busy times, customers should also be prepared to give up their seats."In the end, good manners aren’t about rules — they’re about respect," Grotts said.