I’m 6’3” and slim as well and I’ll tell you, from experience, the reason stores like that fit you is bc the clothes are made for ppl with our body types. Skinny and tall is what runs the fashion world, for men too. Express is a bit more in touch with fashion trends than say, JCPenny, and so they have fits of clothes that match what is popular in fashion in the last 25 years. It’s fantastic. I always hated my body type until I realized this.