In my experience, tension patterns in both body and mind are fueled by self-talk such as "I have to..." rather than, "I could, I would like, I prefer...". The harsh nature of "I have to..." sets up an internal resistance in me that makes me want to rebel. For example, if I tell myself, "I have to lift weights" it's a lot less enjoyable than if I tell myself, "I prefer how I feel when I have completed some strength training".
How we talk to ourselves does make a difference in how we feel about ourselves and the things we need to get done. When possible, it can be helpful to avoid absolutes.