Some things really are better left unsaid, especially if you’re talking to one of the 133 million Americans who live with a chronic illness.

According to the U.S. Centers for Disease Control and Prevention (CDC), nearly half of all American adults live with at least one chronic illness, such as MS, HIV/AIDS, COPD, lupus, Crohn’s disease, and fibromyalgia—to name just a few.

And as anyone with a long-term health issue knows, well-meaning friends, colleagues, relatives, and even strangers will sometimes “put their foot in it”—their intentions are usually good, but without meaning to, they be insulting or cause hurt feelings.

Here are the types of statements you might want to think twice about:

Margit Crane of Seattle, Wash., was diagnosed with fibromyalgia in 1985. She reports that well-meaning people sometimes try to “help” by telling her that she can think her way out of feeling ill.

So beware of suggesting that positive thinking is the cure someone needs. While a positive attitude may help in some situations, you never want to make someone feel bad about feeling bad.

Learn More: What Is Fibromyalgia? »

Pamela Gilchrist, who lives in the greater Cincinnati area and also has fibromyalgia, says that an airline gate agent once even asked her, accusingly, “Why do you need a wheelchair? Do you have cancer?”

According to the CDC, a quarter of people living with chronic conditions say that they experience significant limitations in daily activities, but many of those people don’t have visible symptoms.

In our diet-obsessed culture, it’s easy to assume that all weight loss is welcome. Not so for many people like Cedar Burnett, who has ulcerative colitis. Burnett says, “When I’m really sick with this disease, I can drop 10 pounds in a matter of days … typically, the thinner I am, the sicker I am, so it’s pretty disturbing to hear people congratulate me for weight loss.”

Remember that commenting on someone’s physical appearance—especially if you don’t know him or her very well—is one of the most common ways to put your foot in your mouth!

Take Control: Get Information on Living with Ulcerative Colitis »

Josh Robbins, an HIV activist, blogger, and author, says that he often hears this response when he tells people that he is living with HIV—it’s a pet peeve, and he even created a video about “what not to say to someone who just disclosed their HIV status.” He says, “Instead, I suggest saying, ‘I’m here for you.’”

Keep in mind that a chronic condition is definitely not a funeral. Condolences will likely seem out of place.

Related News: Experts Weigh In on the Newest Way to Prevent HIV »

Mark Black of New Brunswick, Canada, had a heart-lung transplant to deal with chronic congestive heart failure. He points out that empty platitudes about “getting better” can make a person feel misunderstood: Sometimes, he points out, “this is clearly not true.”

Sure, platitudes may have their place, but often a sympathetic ear will help someone with a chronic condition a lot more.

Cynthia McKay is a psychotherapist who works with families dealing with chronic illness—she says that insensitive people often ask whether a person’s smoking, weight, or what-have-you led to a condition. And blame is the last thing that a person whose health has been impacted by an illness or accident needs.

Any comments that lean into “I told you so” territory are going to cause trouble. Before you ask questions like this, ask yourself, “Do I need to know this in order to help or provide support?”

Dave Bexfield runs, a nonprofit website designed to inspire people with multiple sclerosis to stay as active as possible. He notes that diseases like MS are very variable and can affect people in very different ways.

So in addition to asking yourself, “Do I need to know this?” before asking a question, you could also ask yourself, “Is what I’m about to say helpful?” before speaking.

Check Out “You’ve Got This”—Inspirational Videos from People Living with MS »

Writer, speaker, and activist Carly Findlay is living with ichthyosis, a skin condition that affects her appearance and that can be painful. On her blog, she has posted a long list of shouldn’t-have-said-that comments strangers have made—including the doozy above.

Unless you really, really, really know exactly how someone feels, don’t say you do. Instead, ask, “How are you?”—and open yourself up to hearing the answer.

Marisa Zeppieri-Caruana is a board member for the Lupus Foundation of America. She, too, has a blog where she has detailed her least-favorite comments. She says she doesn’t feel “brave” (not having volunteered for lupus) but rather feels “strong.”

There’s a big difference between pity and empathy. And sometimes, you don’t have to say anything. Just being there is enough.

Get the Facts: Q&A with Lupus Expert Dr. Betty Diamond »

Dr. Toral Patel is a dermatologist who often works with patients who are managing chronic skin conditions. She says that we should all beware of “compliments” that also deliver an insult, as this one does.

Sure, compliments are great—but know when to end them.

Ted Meyer of Los Angeles has Gaucher’s disease, an enzyme deficiency. His biggest beef is people who indicate that his rare genetic disorder has a simple cure—herbs or vitamins, for instance—that he’s somehow unaware of.

Lesson: Leave medical advice to the professionals. Depending on a person’s condition, inexpert advice could actually be dangerous.

Psychotherapist Toni Coleman works with many people who have been diagnosed with a chronic or life-altering condition. She says that condescending remarks like these—and her personal favorite, “God never gives us more than we can handle”—only add to a person’s feelings of aloneness.

Avoid measuring a person’s suffering, pain, or discomfort. (And knowing that things could get worse is hardly cheerful news.)

When we’re not feeling well or are frightened about our health, advice is often the last thing we want. What’s more important is simply being listened to—and knowing that we’re being heard.

Larry Berkelhammer, Ph.D., the author of In Your Own Hands: New Hope for People with Chronic Medical Conditions, recommends paraphrasing the key points of what the person with a chronic condition has shared with you.

“Paraphrasing is a particularly effective way of reflecting back what you heard, because then the other person knows that you not only were listening, but that you understood,” Berkelhammer said.

So a sentence like, “I hear you saying that things seem pretty hopeless right now,” or, “It sounds like the pain is really bad todayhow can I help?” opens the door more to an expanded, supportive conversation, unlike unsolicited advice.

Keep in mind that every person is different, and every relationship is different. When in doubt, tread lightly, or even ask how to proceed: “I am here for you, but I’m not sure how to discuss things. Tell me about your condition and what you prefer.”