Stones on the path are as much our teachers, as flowers. Take a moment to accept both with grace.

Injuries could become a serious obstacle in practice.They not only hold you back from doing your practice but also affect your daily life. I have observed this more in students who seem more flexible physically.
If you are starting out, it may be skilful to spend sometime getting your foundations strong, understanding the elements of alignment and some principles to keep you grounded as you move through class.
Working with a teacher or guide may be immensely helpful. Trust yourself and keep in mind your own physical and mental capacity as your approach your mat each day. Do not try to overdo or rush.

My own learning in patience and humility came quite a few years ago as I tried the full split – hanumanasana as shown in the picture below. I got excited with this fancy pose and did not wait for my teacher to complete his instruction. I injured my hamstring and had to modify my practice as it healed for about six months.

For intermediate and higher level students:
If you have been on the mat for a while, chances are you may have tried something you were not ready for, tried to keep up with someone on the mat next to you or simply were in a to rush to go through practice.
A strong ego – ahamkara or an Alpha A type personality could be a hurdle – which is why many texts advocate cultivating a sense of humility and kindness to oneself and others on and off the mat. If you are a teacher, try to present specific modifications to accommodate different students.
It takes a level of conscious awareness in practice to remain focused. Remind yourself of the story of the hare and the tortoise…slow and steady.
Stay safe. Stay happy !