If you continue to practice, improvement is sure to happen. When you stop, the quality of mind goes down. As much as you have practiced, you have already got the result. If you understand this nature, you’re bound to improve if you continue to practice.
Yogis say that they have not improved because they want to see special things. Improvement means that the quality of mind improves, not getting any special experience. Because of expectation, you become bored – you want something new, and that’s craving. Because of craving, you get upset or bored.
If you don’t have expectation, naturally wholesome qualities increase when you continue to practice. Joy, interest, and confidence will grow naturally – it won’t be boring because the mind will be happy and interested to practice. Boredom arises because of craving.