A counter costs you time but rarely costs you the buyer if the gap is small, since a serious buyer who has already gone through the work of writing an offer usually wants to keep negotiating rather than start over on another house.
The bigger risk is countering aggressively on a weak offer and losing the buyer entirely, or accepting too quickly out of relief and leaving room on the table. Knowing which situation you are in depends on how the offer compares to genuinely similar recent sales, not on a gut feeling.
Joel Dyck reviews every offer against real comparables before telling a Saskatoon seller whether to counter or accept. Get your hand-reviewed valuation from Joel Dyck.