We’re taught that if one is forgiving of others, Hashem will be forgiving.
Here are things to be forgiving of in Shul this Rosh Hashanah
1) Time davening is over
2) Niggunim chosen by the Ba’al Tefillah
3) Temperature in the Shul
4) Kibuddim you did or didn’t received
5) The person disturbing your concentration