Irene hates getting sick. She hates the fact that being sick means getting taken care of. Hates the fact that she feels terrible when sick and most importantly hates the fact that when she's sick her members are the ones taking care of her instead of the other way around. But as much as she hates getting sick there's also one perk of being sick that makes it so much more tolerable for her.

It's the fact that Wendy Son Seungwan would take care of her and put all her attention on her. 

Yes, Irene hates being sick. It makes her feel vulnerable and useless, but the moment Son Seungwan opens the door to her room with a worried look on her face, the moment Son Seungwan walks towards her and puts their forehead together to check her temperature, and the moment Son Seungwan bring her food and medicine, feeding her, making sure she eats food, take her medicine and get enough rest. That's when she knows that maybe just maybe being sick is not so bad.