Wizard in heavily embroidered overalls, leaning on his staff as he looks around the ritual room: "It's a nice setup ya got here, ma'am. Real good vibes. So, you were trying to summon your inner demons, you said? And accidentally got one of the big fellas downstairs instead?"
Anxious looking client, poring over her personal grimoire in the hopes of finding answers: "Yes, and I was so careful with my invocations, and I spent hours on the sigils and I busted out the fancy incense and everything and I just don't know what got muddled. It's not my chalk, is it? It says it's certified on the package.."
Wizard: "Nope, your chalk's good quality, you didn't get stiffed there. Your sigils all look good too, and I read the invocations while Gary was driving us over, and they seemed perfectly appropriate. Say hello, Gary."
Gary: "Hi, I'm on a work placement, so I'm shadowing him."
Wizard: "Alright, kid, what's rule number one?"
Gary: "Double check everything. You've gone over the invocations, we've both seen the circle and the materials, there was nothing in the stars last night that ought to have interfered... I'm not sure, honestly. This ritual should have worked."
Wizard: "Uh huh, it's a competently put together rite. So why didn't it work?"
Gary: "Uhhhhhhh... ma'am? Are you currently or have you ever been haunted, or perhaps impugned the Good Neighbours?"
Client: "Not to my knowledge, no."
Wizard: "Good instinct, but here's rule number two for ya, kid. Never assume an otherworldly vendetta when slapdash maintenance is still on the table. Ma'am, do you rent this ritual space?"
Client: "Yes, I don't have the space for a full sanctum at home."
Wizard: "The guy you rented it from hasn't maintained the wards correctly - I assume that was part of the rental agreement?"
Client, outraged: "Yes! It was!"
Wizard, nodding sadly: "Take a look at the threshold, Gary. You see the runes on the doorjamb?"
Gary, squinting: "Uh, barely."
Wizard: "Exactly, they oughta be hummin' away in the back of your mind. But they aren't, because?"
Gary, spinning around in shock: "Oh damn! The door sticks in cold weather, right?"
Gary: "The force of shoving it open has scuffed the carving of some of the runes, brought down the entire ward around the door."
Client: "Bloody fool. Why wouldn't he just carve them deeper?"
Wizard: "Easier to sand down and rent for non ritual purposes, if it comes to that. Doesn't have to replace the whole doorjamb. It can work, but you need to reinforce them with oil and blessed pigment more frequently than you would runes that were carved deep. Every two weeks instead of once a lunar month. Guy's done the bare minimum and is hoping you won't know enough to blame him when things go wrong."
Client: "That incompetent arsehole! I'll haul him in front of the Wizard's Council for this!"
Wizard: "You really should, ma'am. This could have been a lot worse than one of the fellas downstairs popping in. Unwarded portals are a magnet for unspeakable monstrosities from the Dungeon Dimensions. Trust me, once you get those guys infesting your space, you lose all your tools, the space itself and sometimes even your magical name to the purification process. Along with every other ritualist in the building, and the schmuck who caused the problem. What have we learned, Gary?"
Gary: "Double check every ward, every time you invoke?"
Wizard: "Because it only takes forgetting once for something to turn into an eldritch emergency. See, ma'am, he's a bright kid. He's gonna go far in this trade, I'm telling you. Now, let's get you sorted with the grievance forms for the Council."