What we often miss in building relationships is the content. We hear and we speak and our efforts seem to result in bread that does not rise, pudding that falls flat, tasteless main courses, uninteresting regular fare, and empty, heavy calorie desserts.
Let's see how these translate from the world of recipes and food to the other food which also nourishes us: the conversations which build our relationships.

You want a Thanksgiving that is light and goes down well with most people, yet is satisfying. This is like a good loaf of bread. You are afraid the bread cut at the family table will cut to the same emotional hurt that has taken place over and over again, leaving people unsatisfied, unnourished, even angry.

Put more leavening into the dinner bread. Remind yourself beforehand of funny times you have shared with these people, or with other people. Let yourself begin preparations for the holidays with a spirit of lightness by focussing your thoughts on what is positive about your family members.

Then release yourself from results. If you find yourself thinking "If so-and-so says such and such AGAIN, that will be it" stop. Stop and ask yourself what is so enormous about this person's language that you are still, a year or two later, echoing the language to yourself? Create largeness within, like a good bread, by seeing the words roll off your back.
Likely, so-and-so will speak similar language. Now, consider a humourous response.

Make effort with stories. Try to include sweet stories. These may fall a little flat the first time, but be patient. With all relationships, as with all cooking, time and repeat efforts are great allies.

Now to remedy a tasteless main course: spice it up!
Think about a little background music, but go for the spice! A lively salsa, an upbeat classical piece such as Vivaldi's Four Seasons , create a sense of happiness. Search for the music that lifts the room, and put it on during the dinner portion of your day.

You may have a "politician" in your crowd. This is the person who believes family get-togethers are the time to air views about politics. Even if a heated argument does not break out, a heavy silence, a feeling something has been spoiled, may.
As soon as your guest begins, hold up the palm of your hand and say gently "This is not the time or place for this kind of discussion."

Then turn to a positive topics. Have a few on hand, like you would ingredients for a last minute dish!
A positive bit of information about the world goes a long way toward helping everyone feel more comfortably full and satisfyingly fed.

Now for the finale. Avoid the heavy calorie desserts. These are the moments when a family member begins to try to express how they feel, or have felt about every detail of their life with you from the beginning of time.
Or one member may feel it's important to "share" in this way with the general crew or with another individual exactly how it was for him/herself during the time of...
usually some family crisis.

A firm but gentle hand can turn this heavy dessert into something much lighter, something enjoyed by many. Suggest clearly "I understand you need to speak about (the time you felt abandoned, rejected, hurt etc). I feel this is important. Right now, however we are focussed on other things and are not able to give you the audience you need."
Then suggest an after dinner walk, or a game of cards or that everyone help with clean-up!
A little motion helps clear away the overly full sensation of a heavy dessert; likewise a little motion helps clear away the heavier emotional dramas which during family gatherings, are best avoided.