Among my friends and family, I'm know as the photographer and during get-togethers and it's expected, to a point, for me to have a camera with me. I enjoy shooting, so usually it's not a problem, but there are times when you just need to put the camera away. The line can often be blurred, but hopefully this guide will help you realize you don't always need to be behind the lens.
Weddings. When attending a wedding as a guest, have respect for the hired photographer, place of worship the ceremony is happening and the person marrying them. The hired wedding photographer is there to capture the moments, and most ceremonies have guidelines that the professional will follow for where they can be and if a flash is allowed or not. While it's tempting to get your camera out to shoot the whole wedding ceremony, take a few shots of the bride coming down the isle and then sit back and enjoy the wedding. It's both professional courtesy to the hired photography and respect for the couple getting married and the man or woman marrying them.
Vacation. Going on vacation is a no-brainer for amazing photography opportunities, but it's also something you should enjoy and experience with your own eyes, not just through the lens of your camera. Make sure you don't enjoy your vacation by reviewing the photos you took weeks later because the only memories you have are looking through the viewfinder of your camera.
Date night. Your first few dates are probably not the best time to take a camera with you. That time should be spent getting to know the other person, don't ruin it by insisting on taking photographs of what you're doing or of the other person. Further along in the relationship is when you can pull the camera out.
Restaurants. Site's like Yelp give honest, real reviews by average people of restaurants and the food that is served. They thrive on the photos the users submit and businesses are aware of this, so as of late I've personally noticed an increase in the quality of plating and presentation at the better spots in my town. It's not uncommon at all anymore for someone to get their iPhone or camera out to take photos of every plate brought to the table to share in social networks. There is however a time and place for taking photos of your food and the people you are with, which is loosely based on the type of environment you are in. For nicer, sit down restaurants, you don't want annoy other guests with a blazing flash for each course of the meal. Likewise, asking the waiter to take a photo of you and those you are with is acceptable nearly anywhere, but not everyone needs a photo on their own camera. Share the digital file and have respect for the establishment and other guests.
When you are asked to. Take notice next time you walk into your local grocery store, most have a sign on or near the door that forbids photography inside the building. The same goes for most courthouses, some hotels and even gas stations. If you see a sign that forbids photography, or someone isn't comfortable with you taking their photo, be respectful and put the camera away. Even when you aren't asked to, assume in street photography that most people don't want you to take their photos, so if they happen to see the lens pointed in their direction, even if they aren't your subject matter, wait a few minutes and then compose the shot you want, after they've left the field of view.
More or less, it's time to put the camera away during any moment that you should be enjoying what you're doing, not capturing photos of what you should be enjoying. I personally try to take photos of something several times during the week, on a camera phone, point and shoot digital or my DSLR, but they don't run my life. Step back, enjoy the moment for what it is and use your memory now and again to recall it.