Why do programmers choose to write their own code instead of using code that is already available online?

Read also:

• Why Some People Hear Better in Noise Than Others - Neuroscience News
• Meta Agreed to Pay up for Scale AI but Then Wanted More for Its Money - The Information
• What are the best sunscreens for oily skin available in India?
• How can I get rid of the fake girls on social media that are claiming to be hookups? Is there a way to shuffle through them and the real women that actually want to talk?
• Tapping your finger to a specific rhythm boosts brainpower, an unknown human ability just discovered - Earth.com
• Ananda Lewis chose 'natural' cancer care over conventional treatment. Many others do too -- and it's risky - ABC News
• Should You Do Cardio or Weights First? We Finally Have an Answer. - ScienceAlert
• What does the Bible say about the Antichrist? How will we know when he arrives on the scene?
• NASA spots Martian volcano twice the height of Mount Everest bursting through the morning clouds: Space photo of the week - Live Science
• I am 11 years old and I think I am going through puberty. Why do my nipples hurt when I touch them? Is it normal?