Before a runner starts a race, he needs to stretch and jog a few laps to warm-up so he does not hurt himself. The same is with davening. A person should avoid listening or watching things that will disturb his focus during davening. Any thoughts a person will not be able to push aside during the time of davening should be avoided so that everything will be focused on the prayers.
4. Be kind to yourself. Speaking badly even about yourself is unethical.
הלכות שמירת הלשון 