I like to share a powerful tool to gain insight into one's core qualities, pitfalls, allergies and challenges and how they interact: the core quadrant, developed by Daniel Ofman.
Image credits: http://patrickschriel.com/
Here above, the core quadrant is shown, including indicators on how to fill it (too much of.. leads to). In the boxes already some examples are given. You can start filling it from any of the corners, but pitfalls are usually the easiest to start with. Note that the quadrant must be correct all way round ('too much of', 'opposite of').
Now, occasionally might feel a strong allergy with a specific person in a specific situation. The key question then is: which core qualities do their have which sometimes becomes their pitfall (e.g. in stressful situations) and your allergy, or rather: irritation. But most importantly; what can it teach you about your personal challenge as a tool to neutralize the allergy. See the diagram below. Good luck!