Warning: Interview mistakes that could cost you the job

Landing an interview is an exciting milestone in the recruitment process, and your big opportunity to show how your skills, experience, and personality make you the best person for the job. With so much on the line, nerves and uncertainty are natural — but it’s important to avoid common pitfalls that can leave a negative impression. 

Here are some major mistakes to avoid in interviews, and what you should do instead to give yourself the best chance of success. 

Mistake #1: Being underprepared 

Failing to research the position, company, and industry can make you appear uninterested or careless. 

Do This Instead: 

Varavudh Thamrongrat stresses: “You should know what you are applying for.” Thirayada Jantapon adds: “Research the company thoroughly — their profile, core products or services, and main business focus. Look at their leadership team, recent news, and industry reputation.” 

Prepare examples from your own experience that show problem-solving and results. Demonstrating knowledge of the company and industry shows initiative and genuine interest. 

Mistake #2: Being late 

Arriving late gives a poor first impression and suggests you are unprepared. Varavudh highlights: “Don’t be late without a very good reason.”  

Do This Instead: 

Thirayada explains: “In Bangkok, traffic is unpredictable, so plan carefully. Check the route in advance, note the building details such as floor number, and allow time for security checks and lifts. Bring identification — Thai candidates usually use their ID card or driving licence, while non-Thais should carry a passport or at least a copy.” 

For virtual interviews, test your internet connection, platform, lighting, and audio beforehand. If you are delayed, call immediately to inform the interviewer. 

Mistake #3: Looking unprofessional 

Inappropriate attire or poor grooming can undermine your credibility. 

Do This Instead: 

Thirayada advises: “Always dress appropriately. This varies depending on the business, so check beforehand what applies in your case. Follow office rules.” 

Varavudh adds: “If you suspect the office has a ‘shoes off’ culture, choose footwear that looks professional and is easy to remove.” 

Dress one notch above the company’s norm, and for online interviews, wear solid colours. Pay attention to grooming — small details show you care. 

Mistake #4: Overselling yourself 

Trying too hard to impress can make you seem arrogant. 

Do This Instead: 

Thirayada cautions: “No bragging! No ขี้โม้ (kii-mo).” Varavudh agrees: “Be soft, be humble.” 

Confidence is important, but humility and sincerity make a stronger impression. Provide solid examples of achievements — facts and results speak louder than exaggerated claims. 

Mistake #5: Rambling or oversharing 

Nervousness can lead to long, unfocused answers. 

Do This Instead: 

Thirayada and Varavudh advise: “Keep to the point.” Be specific and use keywords. Focus on highlights and keep answers concise — ideally under three minutes for broad questions like “Tell me about yourself.” If you need time to think, pause politely before answering. 

Mistake #6: Being negative 

Criticising past jobs, companies, or managers reflects poorly on you. 

Do This Instead:

Thirayada and Varavudh emphasise: “Don’t blame others or speak negatively.” Instead, stick to facts and highlight positives. If asked why you left a job, focus on your goals for the future rather than problems in the past. Even difficult experiences can be reframed as opportunities for growth. 

Mistake #7: Being forgettable 

Interviewers may meet several candidates in one day, so blending into the crowd is a risk. 

Do This Instead: 

Thirayada reminds: “Remember there are many candidates.” Varavudh adds: “Be yourself.” 

Plan and practice how you present yourself. Share achievements confidently and let your personality show. Offer something memorable — it doesn’t need to be dramatic, just a detail that helps the recruiter remember you. 

Interviews are your chance to shine, but mistakes like being late, unprepared, or negative can cost you the opportunity. Thirayada Jantapon highlights the importance of preparation, politeness, and sincerity, while Varavudh Thamrongrat reminds candidates to be humble, authentic, and themselves. 

By planning carefully, presenting positively, and staying true to your character, you can avoid these pitfalls and give yourself the best chance of landing the job.