I have been involved at the edge of some Tarion claims (working for builders, consultants, condo boards and others).
Good builders want to fix things without a formal claim being registered as the headache exceeds the short-term costs to rectify. Some homeowners are not reasonable. Some builders are not reasonable. Some consultants working for the condo board inflate the list as a negotiating tactic. Tarion doesn't really care. If they get an expert opinion that there is a warrantable defect (and sometimes there are multiple opinions recruited by the parties involved with Tarion normally following the majority opinion), they give the builder a chance to repair and prove fixed and if that doesn't happen in a timely manner, then they go in and do it.
In my experience, they are not vindictive and they won't push for better, they just have a list of defects and if you have some on that list, they need them fixed (typically repaired to the minimum standard required by OBC).
Timely manner is also a point of contention. Home owners want things done asap, some Tarion issues take years to resolve. Homeowners get frustrated with the pace.
If your issue is important to you, but not on the list of warrantable claims for Tarion, it is often just crossed off and it is up to you and your builder to come up with an equitable resolution (which is another reason going with the nuclear option of filing with Tarion is best left until all other avenues have been exhausted).
Builders obviously have more experience and some play the game of stringing you along so you miss important Tarion dates and then your claim is dead if you do choose to file later. It is good to be informed and imo it is a good tactic to know the required Tarion filing dates and use those to keep your builder on track (eg. For identified defects xxx and yyy, if not resolved by the May 15, 2021 filing date required by Tarion, I will need to file to ensure that they are covered and repaired).
