Your question may be coming from a good place, but asking someone why they're not in a relationship is actually quite intrusive and can be hurtful. If the other person is not happy about being single, you may be hitting a sore spot. If they are happy about being single, they probably don't want to be nagged about getting into a relationship.
'When are you two getting married?'
If there are any unwed couples at dinner, don't make them uncomfortable with this question. You don't know what kind of understanding they have with each other, and they probably won't appreciate pressure to get married if they're not ready or don't want to.
Nagging about religious observation
Don't ask someone when was the last time they went to a temple, church, mosque or synagogue, or whether they plan on baptizing their children. Religion is a very personal thing and doesn't look the same for even members of the same family. It's not OK to shame others or impose your own views.
'I have to take this call'
Unless it's an emergency, do your best to be present. While it's totally fine to quickly get some great snapshots of the food for your Instagram, put your phone away at the dinner table. It's quite rude to be texting someone else the whole time when you're there to spend time with your loved ones. Even if you don't know many people or are feeling awkward, being on your phone is not a good idea.
Comments on what others are eating
A big part of Thanksgiving is enjoying the food, so let people do so in peace. Don't comment on how little someone is eating or on their decision to go back for a seconds (unless you're agreeing with them on how delicious those sides are).
Talking about your own diet
Honestly, no one really wants to hear about how you can't eat something because you're on this or that diet, or about how much weight you've lost or gained. Sharing your issues with your body image can make others feel worse about their own bodies. Try to leave your insecurities at home or get rid of them altogether.
'Did you hear what happened with ...?'
There are a lot of reasons why you should never gossip, but it all boils down to the fact that words can actually hurt people. Even if what you're saying never gets back to the person you're talking about, you may upset other people you're around or make things awkward.
Anything negative about another race, religion, sexual orientation or gender
As a general rule, you should try your best to be kind to others. When with family and friends, you may feel comfortable enough to share your opinions, but think twice about what impact your words have on others. Even if you don't think what you're saying applies to anyone in the room, it could apply to someone they care about, or they simply may not want to hear any sort of negativity. It's better to stick to being positive in all your conversations.
'Remember that time you (did some embarrassing thing you hoped everyone forgot)'?
It's also not very nice to make others feel bad by bringing up something that may embarrass them. Even if you think it's funny, try to keep any ribbing of loved ones to things you know they're willing to laugh about.
Bragging about your (or your children's) accomplishments
The urge to show off is understandably strong, especially around family you may not have seen in a while, but try to be humble. It's one thing to mention that you just got a job you're very happy about or that your child just won a scholarship, but it's another to go on and on about how expensive your house is or how all your grandchildren are amazing athletes with perfect hair and fantastic grades. This kind of conversation invites comparison, which can lead to rivalries and resentment.
'When are you having kids?'
Having children is an extremely personal, life-changing decision. Everyone deserves to do so whenever they feel ready, and people also have the right to choose not to have kids at all. A question like this may make an individual or a couple feel pressured, and it can also be a sensitive topic - you never know if someone is having fertility issues or experienced a miscarriage that they haven't shared.
Insulting the food
If someone else has graciously opened their home to you this Thanksgiving, you want to be the best guest you can be. It may seem obvious, but you should be very careful to not insult the food that's been served. This includes saying things like "This needs more salt," or "This is too spicy." Just quietly move on to something else you enjoy more.
'I don't like (certain food)'
It's OK to have food preferences, but it's better if you don't make it known that you're not eating Brussels sprouts because you think they're just stinky little cabbages. Just politely decline and instead bring attention to how much you love other things on the table.
'What are you wearing?!'
Many people try to look their best when attending a party with family or friends, and even if they didn't, you don't want to make anyone feel awkward or terrible for what they're wearing. Whether or not you think their outfit is appropriate or a good fashion choice is irrelevant. It's their personal style, and you don't want them to feel self-conscious for the rest of the night.
Even if you're attending a Thanksgiving dinner at a friend's house where you don't know anyone, try your best to make small talk. Part of being a polite guest is being engaged, and not giving off the impression that you'd rather not be there. Most important of all, you should definitely make sure you don't forget to thank your host and let them know how grateful you are.
More from The Daily Meal:
The 12 People You'll Share the Table With at Every Thanksgiving
21 Most Common Table Etiquette Mistakes
20 Things People Only Say Around the Holidays
The Most Common Turkey Mistakes and How to Avoid Them
Etiquette Mistakes You Need to Stop Making by Age 30