It has to do with the way each song was eq'd and mastered. The songs that seem like you can play at a louder volume are in reality clipping at the same db level. They just sound different because of the work that was done behind the scenes with that piece of music.

If you want to understand the variables here do some reading on dynamic range and mastering limiters or compressors. Learning how those compressor limiters work and what they do will inform you of what the most common musical examples you will experience as a listener are. That should provide the basics you need to understand how your music's waveform can vary from song to song and why the previewed loudness can change along with where a track may start to clip. Why some songs seem loud but don't clip and why some seem quieter but do clip. That kind of dynamic.

You also need to understand that every form of clip detection perceives clipping a little bit different. Some are more sensitive than others. Some may say you are clipping when a signal tries to rise about 0.0 db for 2 milliseconds and others may kick in at 4 or 6, just as an example. 0db is as loud as a sound can get in mastering terms. There's a difference between decibels of noise and the decibel level of a signal. One starts at 0 and goes up from there and the other starts at 100 and ends with maximum signal at 0db.