Using the phrase "You don't want to do that" to tell someone that something is not convenient or advisable is a common conversational tactic. It serves several purposes:

1. Softening the Directive: It's a softer, more indirect way of advising or warning someone against an action. Instead of directly saying "Don't do that" or "That's a bad idea," which might come off as too blunt or authoritative, saying "You don't want to do that" implies consideration for the person's feelings or situation.
2. Implying Consequences: This phrase suggests that there are undesirable outcomes or consequences associated with the action without having to explicitly state what those consequences are. It relies on the listener to infer that there might be reasons or results they haven't considered.
3. Encouraging Reconsideration: By stating it this way, you're inviting the person to think more deeply about the action and its potential impacts. It's a way of prompting someone to pause and reconsider their decision in light of new information or perspectives they might not have considered.
4. Expressing Concern or Care: When said in a certain tone, it can convey concern for the person's well-being or circumstances. It suggests that the speaker has the listener's best interests in mind and is looking out for them.
5. Providing Guidance: Especially in contexts where the speaker has more experience or knowledge about the situation, this phrase can serve as a gentle form of guidance, suggesting that there are reasons based on wisdom or experience why the action might not be the best course.

In practice, the effectiveness and appropriateness of using "You don't want to do that" depend on the relationship between the speaker and the listener, the context in which it is said, and the tone of voice used. It's a versatile phrase that can be friendly and helpful or condescending and dismissive, depending on how it's deployed.

1. Offering Practical Advice: "If you're thinking of going through the old forest trail at night, you don't want to do that; it's not safe."
2. In a Professional Setting: "You don't want to send that email without proofreading it first; it could give the wrong impression."
3. Among Friends: "You're considering texting your ex at 2 AM? Trust me, you don't want to do that."
4. Financial Caution: "Thinking of investing all your savings in that new, untested stock? You really don't want to do that without doing some research first."
5. Parental Guidance: "You don't want to touch the stove while it's hot; it will burn you."
6. Health and Safety: "You don't want to ignore that warning sign about the toxic chemicals in this area."
7. During Travel: "You're planning to walk back to the hotel alone at this hour? You don't want to do that; it's safer to take a taxi."
8. In a Culinary Context: "You don't want to add salt without tasting the soup first; it might already be seasoned enough."
9. While Driving: "You're thinking about texting while driving? You definitely don't want to do that; it's extremely dangerous."
10. Personal Well-being: "You're feeling overwhelmed and want to cancel all your weekend plans to work? You don't want to do that; it's important to take some time to relax and recharge."

Each of these sentences is designed to provide guidance or prevent someone from making a potentially regrettable decision, emphasizing caution and care for the individual's well-being.