Even astrologers who spend most of the day with their noses in ephemerides run into occasional chemistry combustion in their everyday encounters.
Chemistry combustion is a term you will only find on my blog because I just made it up. When you combine two or more of your incompatible planet combos with the incompatible planet combos of another person the results are guaranteed to result in a bad day. Hence the term chemistry combustion.
Ordinarily it is pretty easy for me to avoid chemistry combustion with established relationships because in these relationships I've already gone through the obligatory complimentary mini reading with them which usually took place in a non-astrological social setting when we first met. The planets have been put on the table so to speak and have been stored in my synastry memory bank. This knowledge helps me to tip toe through a wild array of planetary mine fields with the potential to blow. Having the gift of seeing what planetary configurations might cause chemistry combustion is sort of like knowing the secret trigger word of an attack dog. You would never use it around your friends. When used in the right way you can avoid just about anything you'd rather not deal with.
Here are some visuals that may help you understand planetary combusion:
Your reaction to someone's Mars squaring, conjuncting or opposing your Mercury.
How it feels to have someone's Pluto on your ascendant
Your reaction to someone's Jupiter Uranus conjunction on your Moon
Of course these are just my perceptions I suggest meditating on your own and see what you come up with. Happy Aum-ing!