You'll probably annoy other users. If someone reports the post, your post will be reviewed by the moderators and may be edited or removed. You may get a reminder or warning from one of the moderators. If you take the time to review the Forum Rules and avoid the problem in the future, that will be the end of it. The moderators know that anyone can make a mistake and prefer to give users second chances rather than limit their use of the forums.
For repeated breaking of rules or for breaking the most serious rules (e.g., personal insults, harassment, threats, advertising), discipline may be applied even on the first offense. Usually a temporary forum suspension (exclusion) will be applied if previous warnings haven't been sufficient. When excluded you won't be able to access the forums for a certain number of days and will instead see a message about the reason for the suspension. Flagrant violations of serious rules may earn you a permanent suspension, i.e., a forum ban.
For repeated breaking of rules or for breaking the most serious rules (e.g., personal insults, harassment, threats, advertising), discipline may be applied even on the first offense. Usually a temporary forum suspension (exclusion) will be applied if previous warnings haven't been sufficient. When excluded you won't be able to access the forums for a certain number of days and will instead see a message about the reason for the suspension. Flagrant violations of serious rules may earn you a permanent suspension, i.e., a forum ban.