This category affects all data source refreshes, therefore also the initial load at program startup.
Custom images need to be stored in the data source, this results in the size of the configuration becoming problematic if there are too many entries using them. If that becomes the case it would be better to revert to built-in images.
RTF in itself is not a real issue until you decide to embed images in the description. This results in the same problem as using custom images, namely the size of the configuration becoming too large. If that becomes the case, reduce the size of your descriptions.
When you enable the Offline Mode, a local file is created and is kept in sync with the data source. This file is encrypted using the Windows built-in NTFS encryption which can cause delays in refreshing the local data file. This is rarely the case but seems to happen on computers on a domain which has been hardened by the network administrator. You can turn off this option by unchecking Use NTFS Encryption for offline mode in File - Options - Advanced.
The new Ribbon UI is modern and allows for infinite variations of panel organization, but it does take more calculations by the UI layer. On most system this is not a cause for noticeable performance slowdown, but on others setting the User Interface to Classic UI (v7.x) in the general options tab will definitely help.