I am very brand-loyal. Part of that is because I love branding as an industry. Another part of it is that I have trust issues when it comes to quality. The brands I like are very good at showing me what is good quality and what things go together, so I don't have to trust my own judgment so much.
For bags, I like
Coach because they have a large selection that I can see in person and try on. Now that they have re-introduced legacy bags, I feel that if I wait long enough, I'll be able to fill every niche in my wardrobe with smooth leather bags in colors and styles that I love. I think my biggest concern about going with another brand of bag is that it might fall apart more quickly. Why pay more to get something you don't like as well? Also I've established a comfort level with the style, materials, pocket structure, so it almost seems like I am not changing bags every day. And then there is the size: I prefer small shoulder bags, and most of the premiere designer bags I see in person are medium to large bags.
Haven't fallen in love with MK, but if there were a Marc Jacobs or Kate Spade store nearby, I could probably be converted. I also, like Chloe, Celine, Balenciaga and Ferragamo, but the selection and prices keep me from puling the trigger.
For work clothes, I gravitate to Ann Taylor. Used to love Adrienne Vittadini when they had a store. J Crew hasn't drawn me in yet. Don't know why.
For jeans, Gap. The SAs patiently wait for me to try on their wide selection of fits and tell me what looks best.
For furniture, I go straight to Ethan Allen.
For shoes, Coach (for quality and durability) or Dillards, maybe
Nordstrom for a browse.
For coffee creamers, International Delight. Big fan.
Trusting other brands is a lot of extra work for me. One new brand at a time, I guess....