Well, if you put it like that, yeah, it's obvious to me that the right shirt won't make me a better musician. Intellectually, I know that clothes and products won't change my life, make me more skilled or capable, or grant me more time to enjoy my favorite activities. But even though I scoff when I detect advertising that tries to make me feel that way, I generate those feelings in my own head often enough.
Recently I was surfing Etsy for necklaces to wear to work and I came across a bracelet that I thought looked really cool and rock'n'roll, and I could instantly picture myself wearing it while playing bass. Actually, a whole outfit sprang to mind, including the bracelet; a heather gray, relaxed fit, rolled-sleeve, tomboy-femme graphic T (probably a band T-shirt?); skinny dark jeans; and smudged Billie Joe Armstrong-style eyeliner. Instantly my shopping list grew by several items, none of which were appropriate for my original shopping purpose (work).
Furthermore, the chances that I would actually wear these items, if I had them, is low. While I'm trying to dress a bit less schlumpy on my off-time (if only so that I don't feel like going to sleep all the time), the truth is that for the most part I dress for comfort when I'm not at work. There's really not a huge place in my wardrobe for cool, sexy, not-so-comfortable casual clothes. I need, maybe, one such outfit. I also already have skinny jeans I don't wear, and the reason I have no makeup is because it all went bad because I never put it on. I never got into the habit of wearing it in my day-to-day life. It never seemed to be the right occasion.
So I have to ask myself: what makes me think the right occasion would ever occur in the future? This moment I'm imagining--exactly how would this come about? It would be one thing if I played with a band and we were performing; that would be something worse dressing up for. But if I'm just practicing at home? I'm not going to put on a special outfit for that. Dressing up to practice would make me feel pressured and self-conscious. The only reason I can practice now is because I tell myself it's not a big deal. Besides, a bracelet might actually get in the way of playing. If anything, I'd take a bracelet off to play, not put one on.
This isn't the first time I've done this. A couple of summers ago I was convinced that if I got a pair of green hemp pants, I'd spend the whole summer sitting cross-legged outdoors, meditatively smiling at passing dragonflies. I often imagine myself hiking and climbing in prospective jeans, jackets, and sneakers. Cutoff shorts and relaxed navy blue tops make me imagine summer evenings at the beach, digging my toes into the sand.
I think it's good that I tend to vividly visualize myself doing things I enjoy, my perfect life, but what I should do about this is not try to track down the outfit I'm wearing in the daydream. Instead, it's to make time to do the activity I'm enjoying. If a perfect-life daydream is inspired by an ad or an item that I see for sale, my response shouldn't necessarily be to buy the product, but to think about what it really is that I'm craving (more time outdoors, more time spent creatively, more time with friends), make a mental note to chase that directly, and be thankful for the reminder to live life to its fullest.