I will add my voice to the “avoid big box store bikes” chorus. One thing I have not seen mentioned yet is that “real” bikes come in a range of frame sizes. Big box bikes come in ONE size. If you are exactly average height and inseam, they might fit. If you are tall, or short, a bike shop can hook you up with a frame that will accommodate your dimensions.
As a kid, I saved up my paper-route money for a “ten speed”. (it was the 70’s, and 10 speeds was all anybody needed, and we LIKED it). A local department store (anybody remember Denver Dry?) advertised a sale just a little more than my savings, and with a small loan from Dad, I had me a genuine “made in Spain” 10 speed.
I mention that, not to denigrate Spanish manufacturing, but to point out that since Europeans were big into cycling, that should have boded well. It wasn’t to be. That bike was nothing but trouble. The derailleurs were junk, I probably spent more time putting the chain back on than riding. The frame was so soft that dad had to weld reinforcements on at several places. It also hurt me pretty badly twice. Turns out under hard pedaling, the dogs in the freewheel would slip. This is the ratchet mechanism that allows you to coast without the pedals turning. When you are pushing very hard on the pedals, and the freewheel slips, the pedaling resistance suddenly goes from very high to zero. The effect is like when one kid jumps off a teeter-totter, and the other kid comes crashing down. The first time I didn’t know why I suddenly crashed.
I doggedly kept fixing whatever broke next, but finally gave up on it. I could never trust it farther from home than I was willing to push it. I don’t imagine I put more than a couple hundred miles on that bike. When I graduated from high school, my parents wanted to get me a new bike. I insisted that it come from a “real” bike shop…Actually, by then I was much too tall for one-size-fits-all department store bikes. My dad knew what crap that first bike had been, so he was with me, but Mom was slower to get on board…actually, I think it was bought over her objections, but after a year or so of me riding EVERYWHERE and not having to fix anything, I think she realized it was a good deal.
That bike was NOT top-of-the-line. Japanese frame and components, not European. But everything “just worked.” The derailleurs were ridged enough, and their joints not sloppy, so it shifted easily, and stayed in gear. The brakes never dragged, and didn’t shudder. The cables stretched slowly enough that a once-a-year adjustment was all that was needed. The spokes didn’t stretch, and the wheels stayed true. The frame geometry was correct, and it was stable yet responsive. I rode that bike all through college, and commuted to work for a couple of years after that. I rode it in a couple of century (100 miles in a morning) rides. I could keep up all day with my cross-country team, marathon running buddy on his “sears” bike.
After many thousands of miles, that bike died in a crash caused by an inattentive car driver, the frame being bent to the point of making the handling dangerous. In all those miles, the only major thing I had to fix was replacing a rear wheel that got bent in a pothole. I think I changed out the seat to something more comfortable, and put some lighter weight pedals on it, and that was ALL it ever needed.
As others have said, it is a thousand seemingly minor details that make a bike a joy vs. a PITA to ride. A good bike will cause you pain in the wallet ONE TIME. A bad bike will kick you in the ass every time you ride it, and that won’t be very often.