In colloquial American English, What's up? or Wazup? or (t)Zup? or What's happening? or How's it going? etc. are greetings like What's new?, or How are you?. They are not intended to solicit information. The answer to all the What's... questions should be "Nothing" or "Not much." The answer to the How's... questions should be "O.K."
In your paragraph I would use the simple past more. It works great if that is what you're trying to say. I sometimes went to work with my father. I watched him work. I liked the smell...
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