Feel free to add new reasons/excuses in the comments, and others can share their opinions.

// COMMOM BULLSHIT EXCUSES NOT TO APPROACH (which means it's OK to approach in these situations. Some of them REQUIRE an indirect opener)

. She's wearing headphones

. She is walking her dog

. She is with friends

. She is with her mom

. She's with a man (could be a friend)

. She's in a conversation

. She's walking

. She's exercising

. She's reading

. She's working

. Etc

// SOME VALID REASONS NOT TO APPROACH (which means you shouldn't approach. It's ok you're not a wussy)

. She's with a guy (who is OBVIOUSLY her man)

. She's with a baby/kids (personal choice)

. She's walking TOO fast

. At night, dark alley, she's alone (creepy)

. She's too drunk

. She's ugly